Functionalized ionic liquids, and methods of use thereof

ABSTRACT

One aspect of the present invention relates to ionic liquids comprising a pendant Bronsted-acidic group, e.g., a sulfonic acid group. Another aspect of the present invention relates to the use of an ionic liquid comprising a pendant Bronsted-acidic group to catalyze a Bronsted-acid-catalyzed chemical reaction. A third aspect of the present invention relates to ionic liquids comprising a pendant nucleophilic group, e.g., an amine. Still another aspect of the present invention relates to the use of an ionic liquid comprising a pendant nucleophilic group to catalyze a nucleophile-assisted chemical reaction. A fifth aspect of the present invention relates to the use of an ionic liquid comprising a pendant nucleophilic group to remove a gaseous impurity, e.g., carbon dioxide, from a gas, e.g., sour natural gas.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/789,429, filed Apr. 24, 2007, now U.S. Pat. No. 7,744,838; which is adivisional of U.S. patent application Ser. No. 10/407,473, filed Apr. 4,2003, now U.S. Pat. No. 7,208,605; which claims the benefit of priorityto U.S. Provisional Patent Application Ser. No. 60/370,130, filed Apr.5, 2002.

BACKGROUND OF THE INVENTION

Ionic Liquids

Room temperature ionic liquids consist of ions. However, unlikeconventional molten salts (for example, molten sodium chloride), thesematerials often melt below 100° C. Since the melting points are low,ionic liquids can act as solvents in which reactions can be performed,and because the liquid is made of ions rather than molecules, suchreactions often provide distinct selectivities and reactivities ascompared to conventional organic solvents.

Room-temperature ionic liquids have been used as clean solvents andcatalysts for green chemistry and as electrolytes for batteries,photochemistry and electrosynthesis. They have no significant vaporpressure and thus create no volatile organic contaminants. They alsoallow for easy separation of organic molecules by direct distillationwithout loss of the ionic liquid. Their liquid range can be as large as300° C. allowing for large reaction kinetic control, which, coupled withtheir good solvent properties, allows small reactor volumes to be used.Salts based upon poor nucleophilic anions, such as [BF₄]⁻, [PF₆]⁻,[CF₃CO₂]⁻, and [CF₃SO₃]⁻, are water and air insensitive and possessremarkably high thermal stability. Many of these materials are basedaround an imidazolium cation, 1-alkyl-3-methylimidazolium. By changingthe anion or the alkyl chain on the cation, a wide variation inproperties, such as hydrophobicity, viscosity, density and solvation,can be obtained. For example, ionic liquids will dissolve a wide rangeof organic molecules to an appreciable extent, the solubility beinginfluenced by the nature of the counter anion.

The unique physical properties of ionic liquids have been found to offercertain advantages in numerous applications. For example, U.S. Pat. No.5,827,602 to Koch et al. discloses ionic liquids having improvedproperties for application in batteries, electrochemical capacitors,catalysis, chemical separations, and other uses. The ionic liquidsdescribed in Koch et al. are hydrophobic in nature, being poorly solublein water, and contain only non-Lewis acid anions. When fluorinated, theywere found to be particularly useful as hydraulic fluids and inertliquid diluents for highly reactive chemicals. In addition, ionicliquids have been discussed by Freemantle, M. Chem. Eng. News 1998, 76[March 30], 32; Carmichael, H. Chem. Britain, 2000, [January], 36;Seddon, K. R. J. Chem. Tech. Biotechnol. 1997, 68, 351; Welton, T. Chem.Rev. 1999, 99, 2071; Bruce, D. W., Bowlas, C. J., Seddon, K. R. Chem.Comm. 1996, 1625; Merrigan, T. L., Bates, E. D., Dorman, S. C., Davis,J. H. Chem. Comm. 2000, 2051; Freemantle, M. Chem. Eng. News, 2000, 78[May 15], 37. See also Holbrey, J. D.; Seddon, K. R. Clean Products andProcesses 1999, 1, 223-236; and Dupont, J., Consorti, C. S. Spencer, J.J Braz. Chem. Soc. 2000, 11, 337-344.

Ionic liquids have been disclosed for use as solvents for a broadspectrum of chemical processes. These ionic liquids, which in some casescan serve as both catalyst and solvent, are attracting increasinginterest from industry because they promise significant environmentalbenefits, e.g., because they are nonvolatile they do not emit vapors.Hence, for example, they have been used in butene dimerizationprocesses. WO 95/21871, WO 95/21872 and WO 95/21806 relate to ionicliquids and their use to catalyse hydrocarbon conversion reactions suchas polymerisation and alkylation reactions. The ionic liquids describedfor this process were preferably 1-(C₁-C₄ alkyl)-3-(C₆-C₃₀ alkyl)imidazolium chlorides and especially 1-methyl-3-C₁₀ alkyl-imidazoliumchloride, or 1-hydrocarbyl pyridinium halides, where the hydrocarbylgroup is, for example, ethyl, butyl or other alkyl. PCT publication WO01/25326 to Lamanna et al. discloses an antistatic compositioncomprising at least one ionic salt consisting of a nonpolymeric nitrogenonium cation and a weakly coordinating fluoroorganic anion, theconjugate acid of the anion being a superacid, in combination withthermoplastic polymer. The composition was found to exhibit goodantistatic performance over a wide range of humidity levels.

Bronsted Acid Catalysis

From undergraduate laboratories to chemical manufacturing plants, theuse of strong Bronsted acids is ubiquitous. Smith, M. B.; March, J.March's Advanced Organic Chemistry; Wiley-Interscience: New York, 2001;Chapter 8. In this context, solid acids are being more widely usedsince, as non-volatile materials, they are deemed less noxious thantraditional liquid acids. Ritter, S. K. Chem. Eng. News, 2001, 79 (40),63-67. However, solid acids have shortcomings. Among the moretroublesome of these are restricted accessibility of the matrix-boundacidic sites, high mw/active site ratios, and rapid deactivation fromcoking Ishihara, K.; Hasegama, A. and Yamamoto, H. Angew. Chem. Int.Ed., 2001, 40, 4077-4079; and Harmer, M. A. and Sun, Q. Appl. Catal. A:General, 2001, 221, 45-62.

Bearing in mind both the advantages and disadvantages of solid acids,the search continues for systems that are Bronsted acids with solid-likenon-volatility but that manifest the motility, greater effective surfacearea and potential activity of a liquid phase. Combining just thesecharacteristics, ionic liquids (IL) have been described as one of themost promising new reaction mediums. Seddon, K. R. J. Chem. Technol.Biotechnol. 1997, 68, 351-356. Not only can these unusual materialsdissolve many organic and inorganic substrates, they are also readilyrecycled and are tunable to specific chemical tasks. Bates, E. D.;Mayton, R. D.; Ntai, I. and Davis, J. H. Jr. J. Am. Chem. Soc. 2002,124, 926-927; Visser, A. E.; Holbrey, J. D.; Rogers, R. D. Chem.Commun., 2001, 2484-2485; Visser, A. E.; Swatloski, R. P.; Reichert, W.M.; Mayton, R.; Sheff, S.; Wierzbicki, A.; Davis, J. H. Jr.; Rogers. R.D. Chem. Commun., 2001, 135-136; Merrigan, T. L.; Bates, E. D.; Dorman;S. C.; Davis, J. H. Jr. Chem. Commun. 2000, 2051-2052; Forrester, K. J.;Davis, J. H. Jr. Tetrahedron Lett., 1999, 40, 1621-1622; and Morrison,D. W.; Forbes D. C.; Davis, J. H. Jr. Tetrahedron Letters, 2001, 42,6053-6057.

Further, the chemical industry is under significant pressure to replacethe volatile organic compounds that are currently used as solvents inorganic synthesis. Many of these solvents, such as chlorinatedhydrocarbons, are toxic and hazardous for the environment, due to theiremissions in the atmosphere and the contamination of aqueous effluents.Ionic liquids (IL) seem to offer a solution to this problem, too. Ionicliquids have no measurable vapor pressure. This means that they don'tevaporate, and therefore they emit no hazardous vapors in theatmosphere, and replenishing of the solvent is not required. Thisproperty also allows easy separation of volatile products. ILs are ableto dissolve a wide range of organic, inorganic and organometalliccompounds. Notably, their properties can be adjusted by altering thecation or anion of the IL, allowing for fine tuning of the reaction.

Moreover, many organic transformations, such as Fischer esterification,alcohol dehydrodimerization and the pinacol/benzopinacole rearrangement,require an acidic catalyst. Solid acids are now being used since, asnonvolatile compounds, they are less hazardous than traditional liquidacids. As noted above, although they are less hazardous, solid acidshave several disadvantages, such as restricted accessibility of thematrix-bound acidic sites, high molecular weight/active-site ratios, andrapid deactivation from coking Cole, A. C.; Jensen, J. L.; Ntai, I.;Tran, K. L. T.; Weaver, K. J.; Forbes, D. C.; Davis, J. H., Jr. J. Am.Chem. Soc. 2002, 124, 5962-5963.

Purification of Gas Mixtures

There is little doubt that petroleum, coal and natural gas will continueto be the primary global fuel and chemical feedstock sources for someyears to come. Mills, Mark P. Energy Policy in the Electron Age,Mills-McCarthy & Associates, Inc.http://www.fossilfuels.org/electric/electron.htm. Natural gas isregarded as the cleanest of these materials, and as such is beingconsumed at an accelerating pace. Despite its reputation as a cleanfuel, natural gas is usually contaminated with a variety of undesirablematerials, especially CO₂ and H₂S. While this level of contamination isvery low in gas from certain sources (sweet gas), it is much higher ingas from others (sour gas). As sweet gas reserves are depleted,pressures will build for the increased utilization of sour gas. Oil andGas R&D Programs: Securing the U.S. Energy, Environmental and EconomicFuture. Office of Fossil Energy, U.S. Dept. of Energy, Office of NaturalGas and Petroleum Technology: Washington, D.C., 1997. Since admixed CO₂lowers the fuel value of natural gas, the large amount of it present insour gas compels its removal prior to combustion. The lower fuel valuefor sour gas, coupled with the connection between CO₂ and globalwarming, makes CO₂ capture a commercially important and environmentallydesirable process.

One of the most attractive approaches for the separation of a targetcompound from a mixture of gases in a gas stream is selective absorptioninto a liquid. Astarita, G.; Savage, D. W.; Bisio, A. Gas Treating withChemical Solvents; Wiley-Interscience: New York, 1983. Such interactionsbetween gases and pure liquids or solutions are the bases for numerousgas separation technologies, including commercial systems for theremoval of CO₂ from natural gas. These scrubbing processes include onesin which the simple, differential dissolution of the target gas into theliquid phase is of principal importance. More common are processes inwhich a chemical reaction of the target gas with a solute in the liquidphase is the main mode of sequestration. With either mode of gasremoval, the vapor pressure of the solvent itself plays a significantrole in gas-liquid processes, usually to their detriment. In the case oflarge-scale CO₂ capture, aqueous amines are used to chemically trap theCO₂ by way of ammonium carbamate formation. In these systems, the uptakeof water into the gas stream is particularly problematic. Compoundingthe water uptake difficulty is the loss into the gas stream of thevolatile amine sequestering agent.

A liquid that could facilitate the sequestration of gases withoutconcurrent loss of the capture agent or solvent into the gas streamshould prove to be a superior material in such applications. To thisend, ionic liquids (low temperature molten salts) have been proposed assolvent-reagents for gas separations. Pez, G. P.; Carlin, R. T.; Laciak,D. V.; Sorensen, J. C. U.S. Pat. No. 4,761,164. Due to the coulombicattraction between the ions of these liquids, they exhibit no measurablevapor pressure up to their thermal decomposition point, generally >300°C. This lack of vapor pressure makes these materials highly attractivefor gas processing. Indeed, for these purposes they may be thought of as“liquid solids,” incorporating some of the most useful physicalproperties of both phases.

Despite the general promise of ionic liquids (IL) in gas treatment, themolten salts used thus far for CO₂ separation are generally “off theshelf” materials, such as (CH₃)₄NF tetrahydrate, that are not optimizedfor this purpose, frequently depending upon another volatile reagent,water. Pez, G. P.; Carlin, R. T.; Laciak, D. V.; Sorensen, J. C. U.S.Pat. No. 4,761,164; Quinn, R.; Pez, G P. U.S. Pat. No. 4,973,456; andQuinn, R.; Appleby, J. B.; Pez, G. P. J. Am. Chem. Soc., 1995, 117, 329.For instance, the latter salt uses the very weakly basic bifluoride ionto drive the net generation of bicarbonate from CO₂ and water.

The prospects for preparing a broad array of ionic liquids with ionsincorporating functional groups are good. Freemantle, M. Chemical &Engineering News, May 15, 2000, 37. Moreover, certain of these new“task-specific” ionic liquids have proven useful in both synthetic andseparations applications. Visser, A. E.; Holbrey, J. D.; Rogers, R. D.Chem. Commun., 2001, 2484; Visser, A. E.; Swatloski, R. P.; Reichert, W.M.; Mayton, R.; Sheff, S.; Wierzbicki, A.; Davis, J. H. Jr.; Rogers. R.D. Chem. Commun., 2001, 135; Merrigan, T. L.; Bates, E. D.; Dorman; S.C.; Davis, J. H. Jr. Chem. Commun. 2000, 2051; Fraga-Dubreuil, J.;Bazureau J. P. Tetrahedron Lett., 2001, 42, 6097; and Forrester, K. J.;Davis, J. H. Jr. Tetrahedron Lett., 1999, 40, 1621.

SUMMARY OF THE INVENTION

In certain embodiments, the present invention relates to a saltrepresented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a saltrepresented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a saltrepresented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a method ofremoving carbon dioxide, carbonyl sulfide, sulfur dioxide, sulfurtrioxide, hydrogen sulfide or a carbonyl-containing compound from agaseous or liquid mixture, comprising the step of exposing a gaseous orliquid mixture to a salt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a method oftransporting carbon dioxide, carbonyl sulfide, sulfur dioxide, sulfurtrioxide, hydrogen sulfide or a carbonyl-containing compound from afirst gaseous or liquid mixture to a second gaseous or liquid mixture,comprising the step of exposing a first gaseous or liquid mixture to asalt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   exposing subsequently said salt to a second gaseous or liquid        mixture, thereby transporting carbon dioxide, carbonyl sulfide,        sulfur dioxide, sulfur trioxide, hydrogen sulfide or a        carbonyl-containing compound to said second gaseous or liquid        mixture.

In certain embodiments, the present invention relates to a method ofremoving an alkene, alkyne or carbon monoxide from a mixture, comprisingthe step of exposing a mixture to a complex formed from a transitionmetal and a salt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a method ofcatalyzing an acid-catalyzed chemical reaction to give a product,comprising the step of exposing a reactant mixture to a salt selectedfrom the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a method ofcatalyzing a base-catalyzed chemical reaction to give a product,comprising the step of exposing a reactant mixture to a salt selectedfrom the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a method ofpreparing a solution, comprising the step of combining a solute and asolvent to produce a solution, wherein said solvent is selected from thegroup consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts and tabulates the yields for the formation of n-octylether from n-octanol catalyzed bytriphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate,toluenesulfonic acid or Nafion® 117.

FIG. 2 depicts the molar ration of carbon dioxide absorbed to TSIL 1 asa function of time.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described more fully with reference to theaccompanying examples, in which certain preferred embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

Overview of Two Preferred Embodiments

The reaction of triphenylphosphine or N-butylimidazole with cyclicsultones gives zwitterions that are subsequently converted into ionicliquids by reaction with trifluoromethane sulfonic acid or p-toluenesulfonic acid. The resulting ionic liquids have cations to which aretethered alkane sulfonic acid groups. These Bronsted acidic ionicliquids are useful solvent/catalysts for several organic reactions,including Fischer esterification, alcohol dehydrodimerization and thepinacol rearrangement. The ionic liquids combine the low volatility andease of separation from product normally associated with solid acidcatalysts, with the higher activity and yields normally found usingconventional liquid acids.

Reaction of 1-butyl imidazole with 3-bromopropylamine hydrobromide,followed by work-up and anion exchange, yields a room-temperature ionicliquid incorporating a cation with an appended amine group. The ionicliquid reacts reversibly with CO₂, reversibly sequestering the gas as acarbamate salt. The ionic liquid, which can be repeatedly recycled inthis role, is comparable in efficiency for CO₂ capture to commercialamine sequestering reagents, and yet is non-volatile and does notrequire water in order to function.

Bronsted Acidic Ionic Liquids and their Use as Dual Solvents-Catalysts

Remarkably, we have developed the first ionic liquids that are strongBronsted acids. Olivier-Bourbigou, H. and Magna, L. J. Mol. Cat. A:Chemical, 2002, 3484, 1-19; Cole, A. C.; Jensen, J. L.; Ntai, I.; Tran,K. L. T.; Weaver, K. J.; Forbes, D. C.; Davis, J. H., Jr. J. Am. Chem.Soc. 2002, 124, 5962-5963; and Welton, T. Chem. Rev. 1999, 99,2071-2084. In each IL, an alkane sulfonic acid group is covalentlytethered to the IL cation.

The synthetic approach used to assemble the zwitterionic precursors tothe acidic IL is well-precedented. Reaction of the neutral nucleophilesN-butyl imidazole or triphenylphosphine with 1,4-butane sultone or1,3-propane sultone, respectively, produces the requisite zwitterions inexcellent yields. See Yoshizawa, M.; Hirao, M.; Ito-Akita, K. and Ohno,H. J. Mater. Chem. 2001, 11, 1057-1062. In the second step, thesimultaneous realization of the latent acidity of the zwitterions andtheir conversion into ionic liquids is accomplished. The chemical yieldsfor both the zwitterion formation and acidification steps areessentially quantitative. Moreover, since neither reaction producesby-products, the IL syntheses are 100% atom efficient.

The zwitterion acidification is accomplished by combining 1:1 molarquantities of the zwitterions with an acid possessing a pK_(a),sufficiently low to convert the pendant sulfonate group into an alkanesulfonic acid, the pK_(a), of the latter being ˜−2. The result is thetransformation of the zwitterion into an IL cation bearing an appendedsulfonic acid group, with the conjugate base of the exogenous acidbecoming the IL anion. Because these systems contain two formal negativecharges per acidic proton, they may be regarded as internallyself-buffered. For the IL syntheses reported here, the donor acidsincluded trifluoromethane sulfonic acid, p-toluene sulfonic acid hydrate(pTSA.H₂O), sulfuric acid, HPF₄, HPF₆, and (CF₃S(O)₂)₂NH. Two acids werethen used to convert zwitterions 1 and 2 to IL 1a and 2a, respectively.The acidifications were accomplished by stirring together the neatreagents and warming gently for 2-24 h.

Bronsted Acidic IL and the Precursor Zwitterions

The IL 1a is a somewhat viscous liquid at room temperature, while 2a isa stiff glass that liquefies around 80° C. In keeping with the behaviorof other IL, neither 1a or 2a fumes or manifests any observable degreeof vapor pressure, unlike strong acids dissolved in conventional IL,which frequently continue to emit noxious vapors. Further, treatment of1a under vacuum (10 torr) at 150° C. results in no observed loss oftriflic acid (CF₃SO₃H bp=162° C. @ 760 torr) from the IL. Moreover,washing 2a with toluene or diethyl ether results in no extraction offree pTSA (soluble in either liquid). Both of these behaviors areconsistent with the donor acids being fully incorporated into theirrespective IL structures, rather than remaining simply mixtures of addedstrong acid with dissolved zwitterion, in which case some retention ofpre-mixing characteristics (e.g., triflic acid volatility) would beexpected.

Both new IL were screened as solvent/catalysts for several classicalacid-promoted organic reactions, though we placed an emphasis uponprobing the chemistry of 2a (vide infra). The reaction types screenedwere Fischer esterification, alcohol dehydrodimerization and thepinacol/benzopinacole rearrangement. Reactions and results are outlinedbelow in Scheme 1.

Both new ionic liquids proved catalytically active in these reactions.However, we placed an emphasis at this early stage of our studies uponmore fully probing the chemistry of 2a. Our motivation for doing sooriginates in recent reports by Karodia and co-workers in whichtetraorganophosphonium tosylate salts (mp>70° C.) were used as solventsfor several organic reactions. Karodia, N.; Ludley, P. Tetrahedron Lett.2001, 42, 2011-2014; Karodia, N.; Guise, S.; Newlands, C.; Andersen, J.Chem. Commun. 1998, 2341-2342; and Comyns, C.; Karodia, N.; Zeler, S.;Andersen, J. Catal. Lett. 2000, 67, 113-115. In those reports, thecooling of the solvent upon completion of the reaction resulted in theseparation of the IL as a solid. We reasoned that 2a might behavesimilarly, providing direct access to a convenient mode of separation,decantation, which parallels the manner in which solid acids are removedfrom reaction media. As expected, this proved to be the case in most ofthe reactions in which 2a was used.

The reaction of alcohols with strong acids is used both for alkene andether synthesis, the favored product being selected by the judiciouschoice of acid and reaction conditions. Depending upon the substrate/2astoichiometry, 1-octanol is selectively converted to octyl ether in16%-56% isolated yield with minimal by-product formation. In a controlexperiment, pTSA.H₂O gave a better yield of octyl ether but moreby-products were formed and the separation of the pTSA from the reactionmilieu was considerably more difficult. Using Nafion-117^(♦) as acontrol, we found the catalyst/product separation to be straightforwardand by-product formation to be minimal, but the yield of octyl ether wasquite poor (3%).

The rearrangement of pinacol to pinacolone is a process of considerableindustrial importance. The latter provides a synthetic entrée totrimethyl pyruvate and then tent-leucine, a building block of severalpeptidomimetric drugs and chiral catalysts. Stinson, S. E. Chem. Eng.News online at http://www.pubs.acs.org/hotartcl/cenear/960715/page.html.Though existing procedures use H₂SO₄ or H₃PO₄ to catalyze the reaction,interest has been expressed in the replacement of these species by solidacids. Using various solid acid catalysts, reported yields of pinacolonerange from 2%-71%, but long reaction periods are typical, and the use ofa volatile organic solvent is required, complicating isolation. Hsien,M.; Sheu, H.-T.; Lee, T.; Cheng, S. and Lee, J.-F. J. Mol. Cat. A:Chemical 2002, 181, 189-200. Using 2a as catalyst/solvent, we obtainedan unoptimized yield of pinacolone of 35% during a one-hour reactionperiod, and an 88% yield of benzopinacolone over a two-hour period.Moreover, the pinacolone is readily distilled as a pure compoundstraight from the reaction milieu, unreacted pinacol being retained bythe solvent/catalyst phase.

Ultimately, the ease with which these IL are recycled is central totheir utility. Consequently, we examined the formation of ethyl acetate,an important commodity ester, from ethanol and acetic acid using 2a asthe solvent/catalyst in a batch-type process, i.e., recycling the 2a.Otera, J. Angew. Chem. Int. Ed. 2001, 40, 2044-2045. The results of arepresentative round of recycling experiments are summarized below inTable 1.

TABLE 1 Recycling of 2a in the synthesis of ethyl acetate. Ethylacetate, Cycle %^(a) 1 82 2 91 3 96 4 81  5^(b) 87 ^(a)isolated yield.^(b)using regenerated 2a plus water.

As shown, the yield of the ester increases from cycles 1 to 3, only todrop off again in cycle 4. During these cycles, the mass of thesolvent/catalyst medium also increases, consistent with the entrapmentof materials by the cooled catalyst phase. Post-cycling analysis of theIL by GC and NMR was consistent with the retention of appreciablequantities of water and acetic acid. When heated under vacuum to removethese volatile materials, the catalytic activity of 2a was found toincrease, in line with the degree to which water is removed from thesystem.

For an equilibrium reaction in which water is a product, the initialincrease in ester yield accompanying the retention of water in cycles1-3 was unexpected. It appears that for reasons yet to be determined,the presence of a threshold quantity of water in the ionic liquidcontributes to higher reaction yields. To test the plausibility of thistheory, we charged a dried sample of 2a with a bolus of water, estimatedto be equivalent to the cumulative amount retained after cycles 1 and 2;we found the yield (entry 5) of ethyl acetate to be greater than thatobtained using dried 2a (entry 1).

Overall, the IL are versatile solvent/catalysts for the reactionsexamined, and provide further examples of the capacity of ionic liquidsto be fashioned for specific chemical applications. They provide goodproduct selectivities as well as a balance between the yields achievableusing a homogeneous acid catalyst and the ease of catalyst/substrateseparation provided by a heterogeneous catalyst.

Carbon Dioxide Capture by a Task-Specific Ionic Liquid

Remarkably, we have discovered an IL that captures CO₂. The cation ofthis new task-specific ionic liquid consists of an imidazolium ion towhich a primary amine moiety is covalently tethered. This salt readilyand reversibly sequesters CO₂. The ionic liquid is prepared fromcommercially available starting materials. The cation core is assembledby the reaction of 1-butylimidazole with 2-bromopropylamine hydrobromidein ethanol. After 24 h under reflux, the ethanol is removed in vacuo andthe solid residue dissolved in a minimal quantity of water which isbrought to ˜pH 8 by the addition, in small portions, of solid KOH. Theproduct imidazolium bromide is then separated from the KBr by-product byevaporation of the water, followed by extraction of the residue withethanol-THF, in which the imidazolium salt is soluble. Subsequent ionexchange using NaBF₄ in ethanol/water gave the product salt 1 in 58%overall yield. NMR and FAB-MS verify the structure and composition ofthe IL. After drying under vacuum at 80° C., the product is a relativelyviscous, water-free liquid that may be used directly for CO₂sequestration. See Scheme 2.

Consistent with observations by Brennecke and co-workers, CO₂ at 1 atmexhibits intrinsic solubility in the “conventional” ionic liquid phase1-hexyl-3-methyl imidazolium hexafluorophosphate, [6-mim]PF₆. Blanchard,L. A. et al. Nature 1999, 399, 28-31; and Blanchard, L. A. et al. J.Phys. Chem. B 2001, 105, 2437. This is manifested by a 0.0881% increasein mass of the IL upon exposure to CO₂, and also by the FT-IR spectrumof the gas-treated IL, which has peaks characteristic of dissolved CO₂at 2380 and 2400 cm.⁻¹ In a similar fashion, 1 exhibits a mass increasewhen exposed to CO₂, but one that considerably exceeds that observedwith [6-mim]PF₆. When 1.2896 g of pure 1 is exposed to a stream of dryCO₂ for 3 h at 1 atm at room temperature (˜295 K), a total mass gain of0.0948 g (7.4%) is observed, a vastly greater increase than thatobserved for [6-mim]PF₆.

The molar uptake of CO₂ per mole of TSIL during the 3 h exposure periodapproaches 0.5, the theoretical maximum for CO₂ sequestration as anammonium carbamate salt. (See FIG. 2) This per mole uptake of CO₂ by theamine-appended TSIL is comparable to those of standard sequesteringamines, such as monoethanolamine (MEA), β,β′-hydroxyaminoethylether(DGA) and diisopropanolamine (DIPA). The process of CO₂ uptake isreversible; CO₂ extruded from the IL upon heating (80°-100° C.) forseveral hours under vacuum. The recovered ionic liquid has been recycled(five cycles) for CO₂ uptake with no observed loss of efficiency.

Significantly, the sequestration of CO₂ by the TSIL is borne out bycomparison of the FT-IR and NMR spectra of the gas-untreated andgas-treated materials. In the FT-IR, the spectrum of the CO₂ treatedmaterial manifests a new absorption at 1666 cm⁻¹, consistent with acarbamate C═O stretch. Among the other prominent IR changes are thoseassociated with N—H resonances. Centered at 3238 cm⁻¹, a broad amide N—Hband with considerable fine structure is now present. Another broad newband is centered around 3623 cm⁻¹, and is assigned as an ammonium N—Hstretch. Equally noteworthy is the virtual absence of bands associatedwith dissolved CO₂. When subjected to heating under vacuum, the FT-IRspectrum of the sample returns to a pre-CO₂ exposure appearance.

The ¹³C-NMR spectrum of the CO₂ treated product also supports formationof a TSIL-ammonium carbamate. Most notably, a new resonance is observedat δ 158.11, attributable to a carbamate carbonyl carbon. Also new is apeak at 56.52 ppm, consistent with a methylene carbon attached to thecarbamate nitrogen atom. The other features of the spectrum generallyconsist of peaks near those of the starting free-amine TSIL. However,the new resonances are “doubled” due to one-half of the amine TSILbecoming each a carbamate- and an ammonium-appended species.

Various Applications of Ionic Liquids

Ionic liquids that preferentially dissolve certain gaseous species canbe used in conventional gas absorption applications. The non-volatilenature of ionic liquids plays two important roles. First, there will beno cross-contamination of the gas stream by the solvent duringoperation. This means no solvent loss and no air pollution. Second,regeneration of the solvent is easy; a simple flash or mild distillationstep is all that is required to remove the gas from the solvent, againwith no cross-contamination.

In addition to their use as conventional absorbents, ionic liquids maybe immobilized on a support and used in a supported liquid membrane(SLM). The membrane will work if a gas preferentially dissolves in theliquid. SLMs may be used in a continuous separation process without aregeneration step. Conventional SLM technology is undermined by the factthat the liquid in which the gas dissolves eventually evaporates, thusrendering the membrane useless. Since ionic liquids are completelynon-volatile, this problem is eliminated.

Ionic liquids also find use in the conversion of brown coal and oilshale into value-added products, such as alternative synthetic fuelsand/or high-quality chemical feedstocks. For example, 1-butyl-3-methylimidazolium, has been used to extract organic compounds from Estonianoil shale kerogen at various temperatures. Results at 175° C. yieldedsoluble products with an increase of ten times over that obtained usingconventional organic solvents.

Bronsted-acidic ILs also act as proton shuttles, functionally carryingprotons from acidic resin surfaces (e.g., Nafion) to the surroundingmedium, where they are more free to react than if the proton is held atthe polymer surface. Moreover, the Bronsted-acidic ILs have absolutelyno vapor pressure when dissolved in water. For example, a relativelyconcentrated solution of HCl gives off HCl gas; in contrast, aBronsted-acidic IL gives off no gaseous acid—pH paper suspended abovethe surface does not change colors!

Many product streams, particularly in the field of petroleum chemistry,include olefins and non-olefins. For example, ethane crackers tend toproduce a mixture of ethane and ethylene. The ethylene is typicallyseparated from the ethane via distillation. Because the boiling pointsof ethylene and ethane are relatively close to one another, thedistillation is typically done at very low temperatures and/or highpressures; the separation is relatively expensive. The same problems areobserved when separating propane from propylene in dehydrogenationfacilities. Ionic liquids are useful is separating such mixtures. Forexample, an ionic liquid with a pendant functional group thatcoordinates the pi-bond of an olefin may be used to dissolve selectivelythe olefinic components of such a mixture. Likewise, an ionic liquidwith a pendant functional group that coordinates a transition metalcapable of coordinating the pi-bond of an olefin may be used to dissolveselectively the olefinic components of such a mixture. In either case,the dissolved olefins subsequently can be isolated by desorption.

DEFINITIONS

For convenience, certain terms employed in the specification, examples,and appended claims are collected here.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e. to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

The term “ionic liquid” as used herein means an organic salt or hydratethereof with a melting point less than about 150° C.

The term “heteroatom” as used herein means an atom of any element otherthan carbon or hydrogen. Preferred heteroatoms are boron, nitrogen,oxygen, phosphorus, sulfur and selenium.

The term “electron-withdrawing group” is recognized in the art, anddenotes the tendency of a substituent to attract valence electrons fromneighboring atoms, i.e., the substituent is electronegative with respectto neighboring atoms. A quantification of the level ofelectron-withdrawing capability is given by the Hammett sigma (σ)constant. This well known constant is described in many references, forinstance, J. March, Advanced Organic Chemistry, McGraw Hill BookCompany, New York, (1977 edition) pp. 251-259. The Hammett constantvalues are generally negative for electron donating groups (σ[P]=−0.66for NH₂) and positive for electron withdrawing groups (σ[P]=0.78 for anitro group), σ[P] indicating para substitution. Exemplaryelectron-withdrawing groups include nitro, acyl, formyl, sulfonyl,trifluoromethyl, cyano, chloride, and the like. Exemplaryelectron-donating groups include amino, methoxy, and the like.

The term “alkyl” refers to the radical of saturated aliphatic groups,including straight-chain alkyl groups, branched-chain alkyl groups,cycloalkyl (alicyclic) groups, alkyl substituted cycloalkyl groups, andcycloalkyl substituted alkyl groups. In preferred embodiments, astraight chain or branched chain alkyl has 30 or fewer carbon atoms inits backbone (e.g., C₁-C₃₀ for straight chain, C₃-C₃₀ for branchedchain), and more preferably 20 or fewer. Likewise, preferred cycloalkylshave from 3-10 carbon atoms in their ring structure, and more preferablyhave 5, 6 or 7 carbons in the ring structure.

Unless the number of carbons is otherwise specified, “lower alkyl” asused herein means an alkyl group, as defined above, but having from oneto ten carbons, more preferably from one to six carbon atoms in itsbackbone structure. Likewise, “lower alkenyl” and “lower alkynyl” havesimilar chain lengths. Preferred alkyl groups are lower alkyls. Inpreferred embodiments, a substituent designated herein as alkyl is alower alkyl.

The term “aralkyl”, as used herein, refers to an alkyl group substitutedwith an aryl group (e.g., an aromatic or heteroaromatic group).

The terms “alkenyl” and “alkynyl” refer to unsaturated aliphatic groupsanalogous in length and possible substitution to the alkyls describedabove, but that contain at least one double or triple bond respectively.

The term “aryl” as used herein includes 5-, 6- and 7-memberedsingle-ring aromatic groups that may include from zero to fourheteroatoms, for example, benzene, naphthalene, anthracene, pyrene,pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole,pyrazole, pyridine, pyrazine, pyridazine and pyrimidine, and the like.Those aryl groups having heteroatoms in the ring structure may also bereferred to as “aryl heterocycles” or “heteroaromatics.” The aromaticring can be substituted at one or more ring positions with suchsubstituents as described above, for example, halogen, azide, alkyl,aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester,heterocyclyl, aromatic or heteroaromatic moieties, —CF₃, —CN, or thelike. The term “aryl” also includes polycyclic ring systems having twoor more cyclic rings in which two or more carbons are common to twoadjoining rings (the rings are “fused rings”) wherein at least one ofthe rings is aromatic, e.g., the other cyclic rings can be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls.

The terms ortho, meta and para apply to 1,2-, 1,3- and 1,4-disubstitutedbenzenes, respectively. For example, the names 1,2-dimethylbenzene andortho-dimethylbenzene are synonymous.

The terms “heterocyclyl” or “heterocyclic group” refer to 3- to10-membered ring structures, more preferably 3- to 7-membered rings,whose ring structures include one to four heteroatoms. Heterocycles canalso be polycycles. Heterocyclyl groups include, for example, thiophene,thianthrene, furan, pyran, isobenzofuran, chromene, xanthene,phenoxathiin, pyrrole, imidazole, pyrazole, isothiazole, isoxazole,pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole,indole, indazole, purine, quinolizine, isoquinoline, quinoline,phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline,pteridine, carbazole, carboline, phenanthridine, acridine, pyrimidine,phenanthroline, phenazine, phenarsazine, phenothiazine, furazan,phenoxazine, pyrrolidine, oxolane, thiolane, oxazole, piperidine,piperazine, morpholine, lactones, lactams such as azetidinones andpyrrolidinones, sultams, sultones, and the like. The heterocyclic ringcan be substituted at one or more positions with such substituents asdescribed above, as for example, halogen, alkyl, aralkyl, alkenyl,alkynyl, cycloalkyl, hydroxyl, amino, nitro, sulfhydryl, imino, amido,phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio,sulfonyl, ketone, aldehyde, ester, a heterocyclyl, an aromatic orheteroaromatic moiety, —CF₃, —CN, or the like.

The terms “polycyclyl” or “polycyclic group” refer to two or more rings(e.g., cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/orheterocyclyls) in which two or more carbons are common to two adjoiningrings, e.g., the rings are “fused rings”. Rings that are joined throughnon-adjacent atoms are termed “bridged” rings. Each of the rings of thepolycycle can be substituted with such substituents as described above,as for example, halogen, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl,hydroxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate,phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl,ketone, aldehyde, ester, a heterocyclyl, an aromatic or heteroaromaticmoiety, —CF₃, —CN, or the like.

As used herein, the term “nitro” means —NO₂; the term “halogen”designates —F, —Cl, —Br or —I; the term “sulfhydryl” means —SH; the term“hydroxyl” means —OH; and the term “sulfonyl” means —SO₂—.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines, e.g., a moiety that can berepresented by the general formula:

wherein R₉, R₁₀ and R′₁₀ each independently represent a group permittedby the rules of valence.

The term “acylamino” is art-recognized and refers to a moiety that canbe represented by the general formula:

wherein R₉ is as defined above, and R′₁₁ represents a hydrogen, analkyl, an alkenyl or —(CH₂)_(m)—R₈, where m and R₈ are as defined above.

The term “amido” is art recognized as an amino-substituted carbonyl andincludes a moiety that can be represented by the general formula:

wherein R₉, R₁₀ are as defined above. Preferred embodiments of the amidewill not include imides which may be unstable.

The term “alkylthio” refers to an alkyl group, as defined above, havinga sulfur radical attached thereto. In preferred embodiments, the“alkylthio” moiety is represented by one of —S-alkyl, —S-alkenyl,—S-alkynyl, and —S—(CH₂)_(m)—R₈, wherein m and R₈ are defined above.Representative alkylthio groups include methylthio, ethyl thio, and thelike.

The term “carbonyl” is art recognized and includes such moieties as canbe represented by the general formula:

wherein X is a bond or represents an oxygen or a sulfur, and R₁₁represents a hydrogen, an alkyl, an alkenyl, —(CH₂)_(m)—R₈ or apharmaceutically acceptable salt, R′₁₁ represents a hydrogen, an alkyl,an alkenyl or —(CH₂)_(m)—R₈, where m and R₈ are as defined above. WhereX is an oxygen and R₁₁ or R′₁₁ is not hydrogen, the formula representsan “ester”. Where X is an oxygen, and R₁₁ is as defined above, themoiety is referred to herein as a carboxyl group, and particularly whenR₁₁ is a hydrogen, the formula represents a “carboxylic acid”. Where Xis an oxygen, and R′₁₁ is hydrogen, the formula represents a “formate”.In general, where the oxygen atom of the above formula is replaced bysulfur, the formula represents a “thiolcarbonyl” group. Where X is asulfur and R₁₁ or R′₁₁ is not hydrogen, the formula represents a“thiolester.” Where X is a sulfur and R₁₁ is hydrogen, the formularepresents a “thiolcarboxylic acid.” Where X is a sulfur and R₁₁′ ishydrogen, the formula represents a “thiolformate.” On the other hand,where X is a bond, and R₁₁ is not hydrogen, the above formula representsa “ketone” group. Where X is a bond, and R₁₁ is hydrogen, the aboveformula represents an “aldehyde” group.

The terms “alkoxyl” or “alkoxy” as used herein refers to an alkyl group,as defined above, having an oxygen radical attached thereto.Representative alkoxyl groups include methoxy, ethoxy, propyloxy,tert-butoxy and the like. An “ether” is two hydrocarbons covalentlylinked by an oxygen. Accordingly, the substituent of an alkyl thatrenders that alkyl an ether is or resembles an alkoxyl, such as can berepresented by one of —O-alkyl, —O-alkenyl, —O-alkynyl, —O—(CH₂)_(m)—R₈,where m and R₈ are described above.

The term “sulfonate” is art recognized and includes a moiety that can berepresented by the general formula:

in which R₄₁ is an electron pair, hydrogen, alkyl, cycloalkyl, or aryl.

The terms triflyl, tosyl, mesyl, and nonaflyl are art-recognized andrefer to trifluoromethanesulfonyl, p-toluenesulfonyl, methanesulfonyl,and nonafluorobutanesulfonyl groups, respectively. The terms triflate,tosylate, mesylate, and nonaflate are art-recognized and refer totrifluoromethanesulfonate ester, p-toluenesulfonate ester,methanesulfonate ester, and nonafluorobutanesulfonate ester functionalgroups and molecules that contain said groups, respectively.

The abbreviations Me, Et, Ph, Tf, Nf, Ts, Ms represent methyl, ethyl,phenyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl,p-toluenesulfonyl and methanesulfonyl, respectively. A morecomprehensive list of the abbreviations utilized by organic chemists ofordinary skill in the art appears in the first issue of each volume ofthe Journal of Organic Chemistry; this list is typically presented in atable entitled Standard List of Abbreviations. The abbreviationscontained in said list, and all abbreviations utilized by organicchemists of ordinary skill in the art are hereby incorporated byreference.

The term “sulfate” is art recognized and includes a moiety that can berepresented by the general formula:

in which R₄₁ is as defined above.

The term “sulfonylamino” is art recognized and includes a moiety thatcan be represented by the general formula:

The term “sulfamoyl” is art-recognized and includes a moiety that can berepresented by the general formula:

The term “sulfonyl”, as used herein, refers to a moiety that can berepresented by the general formula:

in which R₄₄ is selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl.

The term “sulfoxido” as used herein, refers to a moiety that can berepresented by the general formula:

in which R₄₄ is selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, heterocyclyl, aralkyl, or aryl.

A “selenoalkyl” refers to an alkyl group having a substituted selenogroup attached thereto. Exemplary “selenoethers” which may besubstituted on the alkyl are selected from one of —Se-alkyl,—Se-alkenyl, —Se-alkynyl, and —Se—(CH₂)_(m)—R₇, m and R₇ being definedabove.

Analogous substitutions can be made to alkenyl and alkynyl groups toproduce, for example, aminoalkenyls, aminoalkynyls, amidoalkenyls,amidoalkynyls, iminoalkenyls, iminoalkynyls, thioalkenyls, thioalkynyls,carbonyl-substituted alkenyls or alkynyls.

As used herein, the definition of each expression, e.g. alkyl, m, n,etc., when it occurs more than once in any structure, is intended to beindependent of its definition elsewhere in the same structure.

It will be understood that “substitution” or “substituted with” includesthe implicit proviso that such substitution is in accordance withpermitted valence of the substituted atom and the substituent, and thatthe substitution results in a stable compound, e.g., which does notspontaneously undergo transformation such as by rearrangement,cyclization, elimination, etc.

As used herein, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a broad aspect, thepermissible substituents include acyclic and cyclic, branched andunbranched, carbocyclic and heterocyclic, aromatic and nonaromaticsubstituents of organic compounds. Illustrative substituents include,for example, those described herein above. The permissible substituentscan be one or more and the same or different for appropriate organiccompounds. For purposes of this invention, the heteroatoms such asnitrogen may have hydrogen substituents and/or any permissiblesubstituents of organic compounds described herein which satisfy thevalences of the heteroatoms. This invention is not intended to belimited in any manner by the permissible substituents of organiccompounds.

The phrase “protecting group” as used herein means temporarysubstituents which protect a potentially reactive functional group fromundesired chemical transformations. Examples of such protecting groupsinclude esters of carboxylic acids, silyl ethers of alcohols, andacetals and ketals of aldehydes and ketones, respectively. The field ofprotecting group chemistry has been reviewed (Greene, T. W.; Wuts, P. G.M. Protective Groups in Organic Synthesis, 2^(nd) ed.; Wiley: New York,1991).

Certain compounds of the present invention may exist in particulargeometric or stereoisomeric forms. The present invention contemplatesall such compounds, including cis- and trans-isomers, R- andS-enantiomers, diastereomers, (D)-isomers, (L)-isomers, the racemicmixtures thereof, and other mixtures thereof, as falling within thescope of the invention. Additional asymmetric carbon atoms may bepresent in a substituent such as an alkyl group. All such isomers, aswell as mixtures thereof, are intended to be included in this invention.

If, for instance, a particular enantiomer of a compound of the presentinvention is desired, it may be prepared by asymmetric synthesis, or byderivation with a chiral auxiliary, where the resulting diastereomericmixture is separated and the auxiliary group cleaved to provide the puredesired enantiomers. Alternatively, where the molecule contains a basicfunctional group, such as amino, or an acidic functional group, such ascarboxyl, diastereomeric salts are formed with an appropriateoptically-active acid or base, followed by resolution of thediastereomers thus formed by fractional crystallization orchromatographic means well known in the art, and subsequent recovery ofthe pure enantiomers. Moreover, the enantiomers of a racemic mixture maybe separated using chiral chromatography, e.g., chiral HPLC.

Contemplated equivalents of the compounds described above includecompounds which otherwise correspond thereto, and which have the samegeneral properties thereof (e.g., functioning as analgesics), whereinone or more simple variations of substituents are made which do notadversely affect the efficacy of the compound in binding to sigmareceptors. In general, the compounds of the present invention may beprepared by the methods illustrated in the general reaction schemes as,for example, described below, or by modifications thereof, using readilyavailable starting materials, reagents and conventional synthesisprocedures. In these reactions, it is also possible to make use ofvariants which are in themselves known, but are not mentioned here.

For purposes of this invention, the chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 67th Ed., 1986-87, inside cover.

Compounds of the Invention

In certain embodiments, the present invention relates to a saltrepresented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein Z represents—SO₃H or —N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein L represents(C(R³)₂)_(n).

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein X⁻ representsboron tetrafluoride, phosphorus hexafluoride, methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein X⁻ representsmethanesulfonate, trifluoromethanesulfonate, benzenesulfonate,p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein X⁻ representsbis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; and Z represents —SO₃H or—N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; Z represents —SO₃H or —N(R′)₂;and L represents (C(R³)₂)—.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; Z represents —SO₃H or —N(R′)₂; Lrepresents (C(R³)₂)—; and X⁻ represents boron tetrafluoride, phosphorushexafluoride, methanesulfonate, trifluoromethanesulfonate,benzenesulfonate, p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; Z represents —SO₃H or —N(R′)₂; Lrepresents (C(R³)₂)_(n); and X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; Z represents —SO₃H or —N(R′)₂; Lrepresents (C(R³)₂)_(n); and X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 1 and the attendant definitions, wherein R representsindependently for each occurrence aryl; Z represents —SO₃H or —N(R′)₂; Lrepresents (C(R³)₂)—; and X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein Z represents—SO₃H or —N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein L represents(C(R³)₂)_(n).

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein X⁻ representsboron tetrafluoride, phosphorus hexafluoride, methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein X⁻ representsmethanesulfonate, trifluoromethanesulfonate, benzenesulfonate,p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein X⁻ representsbis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; and Z represents —SO₃Hor —N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; Z represents —SO₃H or—N(R′)₂; and L represents (C(R³)₂)_(n).

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; Z represents —SO₃H or—N(R′)₂; L represents (C(R³)₂)_(n); and X⁻ represents borontetrafluoride, phosphorus hexafluoride, methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; Z represents —SO₃H or—N(R′)₂; L represents (C(R³)₂)_(n); and X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; Z represents —SO₃H or—N(R′)₂; L represents (C(R³)₂)_(n); and X⁻ representsbis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 2 and the attendant definitions, wherein R representsindependently for each occurrence alkyl or aryl; Z represents —SO₃H or—N(R′)₂; L represents (C(R³)₂)_(n); and X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R⁴ representsindependently for each occurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R⁵ representsindependently for each occurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R⁵ representsindependently for each occurrence alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein Z represents—SO₃H or —N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein L represents(C(R³)₂)_(n).

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein X⁻ representsboron tetrafluoride, phosphorus hexafluoride, methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein X⁻ representsmethanesulfonate, trifluoromethanesulfonate, benzenesulfonate,p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein X⁻ representsbis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; and Z represents —SO₃H or—N(R′)₂.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;and L represents (C(R³)₂)_(n).

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); and X⁻ represents boron tetrafluoride,phosphorus hexafluoride, methanesulfonate, trifluoromethanesulfonate,benzenesulfonate, p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)—; and X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); and X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); and X⁻ representsbis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents boron tetrafluoride, phosphorushexafluoride, methanesulfonate, trifluoromethanesulfonate,benzenesulfonate, p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; and R⁴ represents independently for eachoccurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide; and R⁴represents independently for each occurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; and R⁴ represents independently for eachoccurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ representsbis(trifluoromethanesulfonyl)amide; and R⁴ represents independently foreach occurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents boron tetrafluoride, phosphorushexafluoride, methanesulfonate, trifluoromethanesulfonate,benzenesulfonate, p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide; R⁴ representsindependently for each occurrence H or alkyl; and R⁵ representsindependently for each occurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ representsbis(trifluoromethanesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence H or alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents boron tetrafluoride, phosphorushexafluoride, methanesulfonate, trifluoromethanesulfonate,benzenesulfonate, p-toluenesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents methanesulfonate,trifluoromethanesulfonate, benzenesulfonate, p-toluenesulfonate,bis(methanesulfonyl)amide, bis(trifluoromethanesulfonyl)amide,bis(benzenesulfonyl)amide, or bis(p-toluenesulfonyl)amide; R⁴ representsindependently for each occurrence H or alkyl; and R⁵ representsindependently for each occurrence alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence alkyl.

In certain embodiments, the present invention relates to a saltrepresented by 3 and the attendant definitions, wherein R representsindependently for each occurrence alkyl; Z represents —SO₃H or —N(R′)₂;L represents (C(R³)₂)_(n); X⁻ representsbis(trifluoromethanesulfonyl)amide; R⁴ represents independently for eachoccurrence H or alkyl; and R⁵ represents independently for eachoccurrence alkyl.

Methods of the Invention

In certain embodiments, the present invention relates to the use of anIL with an appended amine (e.g., primary, secondary, tertiary, orheterocyclic) for the capture from the gas phase of an acidic gas,including but not limited to H₂S, CO₂, COS, SO₂, and SO₃.

In certain embodiments, the present invention relates to the use of anIL with an appended amine (e.g., primary, secondary, tertiary, orheterocyclic) in conjunction with water for the capture of an acidic gasfrom the gas phase.

In certain embodiments, the present invention relates to the use of anIL with an appended amine (e.g., primary, secondary, tertiary, orheterocyclic) dissolved in a molecular solvent or other ionic liquid forthe capture of an acidic gas from the gas phase.

In certain embodiments, the present invention relates to the use of anIL with an appended amine dissolved in water or other solvent as anon-odorous, non-volatile base for a general-base-catalyzed reaction.

In certain embodiments, the present invention relates to the use of anIL with an appended amine as a scavaging agent for an amine-reactivematerial in the solution phase.

In certain embodiments, the present invention relates to the use of anIL with an appended amine as a solvent.

In certain embodiments, the present invention relates to the use of anIL with an appended amine (e.g., primary, secondary, tertiary orheterocyclic) alone or in conjunction with an organic molecule, such assalicylaldehyde, for the extraction of a metal ion from an aqueoussolution.

In certain embodiments, the present invention relates to the use of anIL with an appended amine in conjunction with an ion-exchange resin,clay or zeolite for any of the aforementioned applications.

In certain embodiments, the present invention relates to the use of anIL with an appended acidic group for general or specific acid catalysis,either as a pure material, or as a solution in another ionic liquid ormolecular solvent. Such reactions include, but are not limited to,Fischer esterification, pinnacol rearrangement, alcohol dehydration,rearrangements, isomerizations, Friedel-Crafts alkylation and acylation,or aromatic nitration.

In certain embodiments, the present invention relates to the use of anIL with an appended acidic group as a scavaging agent for anacid-reactive material in the gas or solution phase.

In certain embodiments, the present invention relates to the use of anIL with an appended acidic group as a dehydrating or drying agent.

In certain embodiments, the present invention relates to the use of anIL with an appended acid in conjunction with an ion-exchange resin, clayor zeolite for any of the aforementioned applications.

In certain embodiments, the present invention relates to the use of anIL with an appended acidic group as a solvent.

In certain embodiments, the present invention relates to the use of anIL with an appended fluoroketone or fluoroalcohol group as a solvent; asan acid; or as an activator of peroxide for use in an oxidationreaction.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfone, sulfoxide or sulfonamide group in aliquid-liquid or liquid-gas separation, including a separation in therefining of petroleum or petrochemicals.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfone, sulfoxide or sulfonamide group as a solventfor a polar molecule, including but not limited to biomolecules, such assaccharides, amino acids, nucleic acids, proteins, enzymes, DNA and RNA.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfone, sulfoxide or sulfonamide group as asolvent.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfone, sulfoxide or sulfonamide group as aphase-transfer adjuvant for use in conjunction with a supercriticalsolvent, e.g., supercritical CO₂.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfonyl halide group as a scavaging reagent for usein conjunction with a reactive species.

In certain embodiments, the present invention relates to the use of anIL with an appended sulfone or sulfoxide group in conjunction with ionexchangeable materials, such as ion exchange resins, clays, andzeolites, for any of the aforementioned uses.

In certain embodiments, the present invention relates to the use of anIL with an appended amide, urea or thiourea group in a liquid-liquid orliquid-gas separation, including separations in the refining ofpetroleum or petrochemicals.

In certain embodiments, the present invention relates to the use of anIL with an appended amide, urea or thiourea group as a solvent for apolar molecule, including but not limited to biomolecules, such assaccharides, amino acids, nucleic acids, proteins, enzymes, DNA and RNA.

In certain embodiments, the present invention relates to the use of anIL with an appended amide, urea or thiourea group as a solvent.

In certain embodiments, the present invention relates to the use of anIL with an appended amide, urea or thiourea group in conjunction with anion exchangeable material, such as ion exchange resins, clays, andzeolites, for any of the aforementioned uses.

In certain embodiments, the present invention relates to the use of anIL with an appended amide, urea or thiourea group as a phase-transferadjuvant for use in conjunction with a supercritical solvent, e.g.,supercritical CO₂.

In certain embodiments, the present invention relates to the use of aphosphoramide appended IL, alone or in conjunction with another ionicliquid or a molecular solvent, as a solvent or for the extraction of ametal from an ore or immiscible solution phase.

In certain embodiments, the present invention relates to the use of afunctionalized IL as a solvent, reagent-solvent, or a catalyst-solventfor a polymerization or a polymer-processing operation.

In certain embodiments, the present invention relates to the use of afunctionalized IL as an anti-static agent, e.g., in a solution,petroleum or a petrochemical.

In certain embodiments, the present invention relates to a method ofremoving carbon dioxide, carbonyl sulfide, sulfur dioxide, sulfurtrioxide, hydrogen sulfide or a carbonyl-containing compound from agaseous or liquid mixture, comprising the step of exposing a gaseous orliquid mixture to a salt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —N(R′)₂.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidgaseous or liquid mixture is natural gas.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein carbondioxide is removed.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein the salt isdissolved in water.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —N(R′)₂; and said gaseousor liquid mixture is natural gas.

In certain embodiments, the present invention relates to a method oftransporting carbon dioxide, carbonyl sulfide, sulfur dioxide, sulfurtrioxide, hydrogen sulfide or a carbonyl-containing compound from afirst gaseous or liquid mixture to a second gaseous or liquid mixture,comprising the step of exposing a first gaseous or liquid mixture to asalt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   exposing subsequently said salt to a second gaseous or liquid        mixture, thereby transporting carbon dioxide, carbonyl sulfide,        sulfur dioxide, sulfur trioxide, hydrogen sulfide or a        carbonyl-containing compound to said second gaseous or liquid        mixture.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —N(R′)₂.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein said saltis contained within a semi-permeable membrane.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —N(R′)₂; and said salt iscontained within a semi-permeable membrane.

In certain embodiments, the present invention relates to a method ofremoving an alkene, alkyne or carbon monoxide from a mixture, comprisingthe step of exposing a mixture to a complex formed from a transitionmetal and a salt selected from the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence alkenyl or alkynyl; and thetransition metal is selected from groups 8-11 of the Periodic Table.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence alkenyl or alkynyl; and thetransition metal is iron, cobalt, nickel, copper, ruthenium, rhodium,palladium, silver, iridium or platinum.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence alkenyl or alkynyl; and thetransition metal is silver.

In certain embodiments, the present invention relates to a method ofcatalyzing an acid-catalyzed chemical reaction to give a product,comprising the step of exposing a reactant mixture to a salt selectedfrom the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H or —CO₂H;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises an alcohol; and said product is an ether.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises an alcohol and a carboxylic acid; and saidproduct is an ester.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises an ester and water; and said product is acarboxylic acid.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises an alcohol and a first ester; and saidproduct is a second ester.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises a 1,2-diol; and said product is a ketone.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises an alcohol; and said product is an alkene.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises a first alkene; and said product is a secondalkene.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises a first aromatic compound and a nitratingagent; and said product is a second aromatic compound comprising a nitrogroup.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises a first aromatic compound and an alcohol; andsaid product is a second aromatic compound comprising an alkyl group.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein saidreactant mixture comprises a first aromatic compound and a carboxylicacid; and said product is a second aromatic compound comprising an acylgroup.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; and said reactantmixture comprises an alcohol; and said product is an ether.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; and said reactantmixture comprises an alcohol and a carboxylic acid; and said product isan ester.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; and said reactantmixture comprises an ester and water; and said product is a carboxylicacid.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; and said reactantmixture comprises an alcohol and a first ester; and said product is asecond ester.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; and said reactantmixture comprises a 1,2-diol; and said product is a ketone.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; said reactantmixture comprises an alcohol; and said product is an alkene.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; said reactantmixture comprises a first alkene; and said product is a second alkene.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; said reactantmixture comprises a first aromatic compound and a nitrating agent; andsaid product is a second aromatic compound comprising a nitro group.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; said reactantmixture comprises a first aromatic compound and an alcohol; and saidproduct is a second aromatic compound comprising an alkyl group.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —SO₃H; said reactantmixture comprises a first aromatic compound and a carboxylic acid; andsaid product is a second aromatic compound comprising an acyl group.

In certain embodiments, the present invention relates to a method ofcatalyzing a base-catalyzed chemical reaction to give a product,comprising the step of exposing a reactant mixture to a salt selectedfrom the group consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;

R⁴ represents independently for each occurrence H, alkyl, fluoroalkyl,aryl, heteroaryl, aralkyl, heteroaralkyl, formyl, acyl,alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,arylaminocarbonyl, or —(CH₂)_(n)—R₈;

-   -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —N(R′)₂, —OR′, —SR′, or —C(OR′)(R″)₂;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

In certain embodiments, the present invention relates to theaforementioned method and the attendant definitions, wherein Zrepresents independently for each occurrence —N(R′)₂.

In certain embodiments, the present invention relates to a method ofpreparing a solution, comprising the step of combining a solute and asolvent to produce a solution, wherein said solvent is selected from thegroup consisting of:

-   -   salts represented by 1:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive;        -   salts represented by 2:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈; or ⁺NR₃ taken together        represents pyridinium, imidazolium, benzimidazolium, pyrazolium,        benzpyrazolium, indazolium, thiazolium, benzthiazolium,        oxazolium, benzoxazolium, isoxazolium, isothiazolium,        imdazolidenium, guanidinium, quinuclidinium, triazolium,        tetrazolium, quinolinium, isoquinolinium, piperidinium,        pyrrolidinium, morpholinium, pyridazinium, pyrazinium,        piperazinium, triazinium, azepinium, or diazepinium;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive; and        -   salts represented by 3:

wherein

-   -   R represents independently for each occurrence alkyl,        fluoroalkyl, cycloalkyl, aryl, heteroaryl, aralkyl,        heteroaralkyl, or —(CH₂)_(n)—R₈;    -   R′ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R″ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   R³ represents independently for each occurrence H, F, or alkyl;    -   R⁴ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, formyl,        acyl, alkyloxycarbonyl, aryloxycarbonyl, alkylaminocarbonyl,        arylaminocarbonyl, or —(CH₂)_(n)—R₈;    -   R⁵ represents independently for each occurrence H, alkyl,        fluoroalkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, or        —(CH₂)_(n)—R₈;    -   L represents (C(R³)₂)_(n), (C(R³)₂)_(n)J(C(R³)₂)_(m), or        (C(R³)₂)_(n)Ar(C(R³)₂)_(m);    -   Z represents —SO₃H, —CO₂H, —CO₂R, —C(O)N(R″)₂, —C(O)N(R″)N(R″)₂,        —N(R′)₂, —OR′, —SR′, —S(O)R″, —S(O)₂R″, —CN, —N(R″)P(O)(R)₂,        —C(OR′)(R″)₂, alkenyl, or alkynyl;    -   Ar represents independently for each occurrence aryl or        heteroaryl;    -   J represents independently for each occurrence O, S, NR′,        cycloalkyl, or heterocyclyl;    -   X⁻ represents boron tetrafluoride, phosphorus tetrafluoride,        phosphorus hexafluoride, alkylsulfonate, fluoroalkylsulfonate,        arylsulfonate, bis(alkylsulfonyl)amide,        bis(fluoroalkylsulfonyl)amide, bis(arylsulfonyl)amide,        (fluoroalkylsulfonyl)(fluoroalkylcarbonyl)amide, halide,        nitrate, nitrite, sulfate, hydrogensulfate, alkyl sulfate, aryl        sulfate, carbonate, bicarbonate, carboxylate, phosphate,        hydrogen phosphate, dihydrogen phosphate, hypochlorite, or an        anionic site of a cation-exchange resin;    -   R₈ represents independently for each occurrence cycloalkyl,        aryl, or heteroaryl;    -   m represents independently for each occurrence an integer in the        range 1-10 inclusive; and    -   n represents independently for each occurrence an integer in the        range 1-10 inclusive.

EXEMPLIFICATION

The invention now being generally described, it will be more readilyunderstood by reference to the following examples, which are includedmerely for purposes of illustration of certain aspects and embodimentsof the present invention, and are not intended to limit the invention.

Example 1 Brønsted Acidic Ionic Liquids and their Use asCatalysts-Solvents

General Considerations

¹H NMR (300 MHz) and ¹³C NMR (75 MHz) spectra were obtained as solutionsin either CDCl₃ or D₂O. Chemical shifts were reported in parts permillion (ppm, δ) and referenced to CHCl₃ (δ 7.27) or D₂O (δ 4.88).Infrared spectra were recorded as a thin film on sodium chloride andabsorptions were reported in wavenumbers (cm⁻¹). Melting points areuncorrected. Distillations were performed using a Kugelrohr ball-tubedistillation apparatus. Gas chromatographic analyses were performedusing an Agilent 6850 system (FID). TLC analyses were performed onWhatman flexible polyester backed TLC plates with a fluorescentindicator. Detection was conducted by UV absorption (254 nm) andcharring with 10% KMnO₄ in water. Baker silica gel (47-61 microns) wasused for all chromatographic separations Anhydrous organic solvents weredried and then distilled prior to use. Acetic acid, acetic anhydride,benzopinacole, ethanol, hexanoic acid, 1-octanol, pinacol andp-toluenesulfonic acid were not purified prior to use. All otherchemicals used for synthetic procedures were reagent grade or better.Solutions were concentrated in vacuo with a rotary evaporator and theresidue was purified using a silica gel column unless specifiedotherwise.

Synthesis of triphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate

Triphenylphosphine and 1,3-propane sultone were combined in equimolarquantities in toluene and brought to reflux. Overnight, a whiteprecipitate formed which was isolated by filtration and dried. Analysisof the solid revealed it to be the desired zwitterion, formed inquantitative yield. The desired zwitterion was of sufficient purity tobe used without any further purification. Conversion to the ionic liquidwas accomplished by combining equimolar quantities of pTSA hydrate andthe zwitterion and heating to 70° C. for 24 h, during which time thesolids liquefy, resulting in the formation oftriphenyl(propyl-3-sulfonyl)phosphonium toluenesulfonate. The IL phasewas then washed repeatedly with toluene and ether to remove non-ionicresidues, and dried in vacuo. The product was formed quantitatively andin high purity as assessed by mass balance and NMR spectroscopy.Spectral data: ¹H NMR (300 MHz, D₂O); δ 7.66-7.60 (m, 3H), 7.53-7.44 (m,14H), 7.06 (d, J=8.0, 2H), 3.31-3.21 (m, 2H), 2.89 (t, J=6.9, 2H), 2.11(s, 3H), 1.97-1.80 (m, 2H). ¹³C NMR (75.5 MHz, D₂O); δ 142.21, 139.75,135.29, 135.25, 133.47, 133.34, 130.40, 130.23, 129.42, 125.44, 118.13,116.98, 50.55, 50.33, 20.58, 20.04, 17.9.

Synthesis of Benzopinacolone(2,2,2-triphenylacetophenone)

To a 5 mL reaction conical vial equipped with stir bar and refluxcondenser was added 882 mg triphenyl(propyl-3-sulphonyl)phosphoniumtoluenesulfonate. Next added in one portion was 58.8 mg benzopinacole.The reaction was allowed to warm to 140° C. for a period of 2 hours. Theresulting monophase was then allowed to cool to room temperature atwhich time the biphase was washed with EtOAc (3×2.0 mL) after additionof 1.0 mL water and 2.0 mL EtOAc. The combined organic phases were driedwith anhydrous MgSO₄, filtered and concentrated in vacuo. The crudeproduct (71.1 mg) revealed over a 99% conversion from benzopinacole tobenzopinacolone via GC ((HP-1 methyl siloxane) 100° C. (2 min), 10°C./min, 275° C. (10 min)) 11.32 min (benzopinacole); 21.38 min(benzopinacolone). Purification by silica gel chromatography (EtOAc/Hex1:8) afforded the desired material in 49.5 mg (88% isolated yield) as awhite crystalline solid. Spectral data of this material matched that ofcommercially available material.

Synthesis of n-octyl ether

To a 5 mL reaction conical vial equipped with stir bar and refluxcondenser was added 1.0 g (1.91 mmol)triphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate. Next added inone portion was 1.0 mL (6.35 mmol) 1-octanol. The reaction was allowedto warm to 175° C. over a period of 2 hours. The resulting monophase wasthen allowed to cool to room temperature at which time the biphase waswashed with EtOAc (3×2.0 mL) after addition of 1.0 mL water and 2.0 mLEtOAc. The combined organic phases were dried with anhydrous MgSO₄,filtered and concentrated in vacuo. Purification by bulb-to-bulbdistillation (bp 130° C./3 mm Hg (air bath temp)) afforded the desiredmaterial in 432 mg (56% isolated yield) as a clear and colorless oil.

The ratio of alcohol to IL effected the overall yield of octyl etherformation. From the combination of approximately 300 mg (0.57 mmol)triphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate and 0.45 mL1-octanol, afforded was 55 mg (16% isolated yield), whereas from thecombination of 771 mg (1.47 mmol)triphenyl(propyl-3-sulphonyl)phosphonium toluenesulfonate and 0.5 mL(3.18 mmol) 1-octanol, afforded was 96.8 mg (25% isolated yield). Theproducts in each run were analyzed by GC ((HP-1 methyl siloxane) 100° C.(2 min), 10° C./min, 275° C. (10 min)) 4.83 min (1-octanol); 12.03 min(octyl ether) and confirmed by NMR. Spectral data of this materialmatched that of commercially available material.

Control Reaction using PTSA: From the combination of 1-octanol (0.5 mL,3.17 mmol) and p-toluenesulfonic acid (280 mg, 1.47 mmol (using themonohydrate)) was obtained 187 mg n-octyl ether (49% isolated yield)based upon purification of the crude product by bulb-to-bulbdistillation (bp 130° C./3 mm Hg (air bath temp)).

Control Reaction using NAFION 117: From the combination of 0.5 mL1-octanol (3.17 mmol) and 0.314 g NAFION 117 (0.28 meq (0.89 meq/g)) in3.0 mL toluene (1.1 M) as solvent was obtained 12.4 mg n-octyl ether (3%isolated yield) upon purification of the crude product (GC ratio of90:10 (octanol:octyl ether)) by bulb-to-bulb distillation (bp 130° C./3mm Hg (air bath temp)).

Synthesis of pinacolone(3,3-dimethyl-2-butanone)

A 5 mL reaction conical vial was equipped with stir bar andHinkman-Hinkle still head. Attached onto the still head was a refluxcondenser with drying tube. To the reaction conical vial was addedapproximately 1.0 g triphenyl(propyl-3-sulphonyl)phosphoniumtoluenesulfonate. Next added in one portion to the reaction vial was 290mg pinacol. The reaction was allowed to warm to a maximum temperature of180° C. for a total period of 1 hour. The resulting monophase was thenallowed to cool to room temperature at which time the distillate wastransferred to another flask and analyzed by GC ((HP-1 methyl siloxane)50° C. (2 min), 10° C./min, 275° C. (10 min)) 4.07 min (pinacolone);6.17 min (pinacol) and NMR. Purification of the crude product viabulb-to-bulb distillation (bp 125° C./3 mm Hg (air bath temp)) affordedthe desired material in 86 mg (35% isolated yield) as a clear andcolorless oil. Spectral data of this material matched that ofcommercially available material.

Synthesis of 3-butyl-1-(butyl-4-sulfonyl)imidazoliumtrifluoromethanesulfonate

From the combination of 1-butylimidazole and 1,4-butane sultone wasformed in excellent yield. After washing the salt with diethyl ether andtoluene to remove any unreacted starting materials, the solid was driedin vacuo. Then, a stoichiometric amount of trifluoromethanesulfonic acidwas added and the mixture stirred for two hours at 40° C. during whichtime the solid zwitterion dissolved/liquefied, resulted in the formationof 3-butyl-1-(butyl-4-sulfonyl)imidazolium trifluoromethanesulfonate.The IL phase was then washed repeatedly with toluene and ether to removenon-ionic residues, and dried in vacuo. The product was formedquantitatively and in high purity as assessed by mass balance and NMRspectroscopy. Spectral data: ¹H NMR (300 MHz, D₂O); δ 8.68 (s, 1H), 7.40(d, J=1.6, 1H), 7.39 (d, J=1.6, 1H), 4.13 (t, J=6.9, 2H), 4.08 (t,J=7.1, 2H), 2.82 (t, J=7.4, 2H), 1.91 (quint, J=8.0, 2H), 1.73 (q,J=7.7, 2H), 1.68-1.57 (m, 2H), 1.19 (dt, J=7.7, 7.7, 2H), 0.79 (t,J=7.4, 3H). ¹³C NMR (75.5 MHz, D₂O) δ 135.26, 122.64, 122.42, 119.80 (q,J_(C-F)=317.0, CF₃), 50.22, 49.49, 49.10, 31.31, 28.26, 21.11, 18.88,12.75.

Synthesis of n-octyl hexanoate

To a 5 mL reaction vial equipped with stir bar was added approximately200 μL of 3-butyl-1-(butyl-4-sulfonyl)imidazoliumtrifluoromethanesulfonate (1.9 M). Added next via syringe was 1-octanol(60 μL, 0.38 mmol) followed by hexanoic acid (48 μL, 0.38 mmol). Theresulting monophase was allowed to stir at room temperature for a periodof 7 days at which time the oil was washed with toluene (5×2 mL).Shorter reaction times using higher reaction temperatures also affordedexcellent conversion of acid to ester. Reaction of 1-octanol and aceticacid resulted in 89% conversion to n-octyl acetate at 40° C. for aperiod of 72 h whereas 83% conversion was observed at 40° C. for 48 h.The collected organic washes were concentrated in vacuo to afford 76 mgof n-octyl hexanoate. GC analysis of the crude product revealed onlytrace amounts of starting material in the organic washes. Purificationof the crude colorless oil by bulb-to-bulb distillation afforded thedesired compound in 72 mg (0.31 mmol, 82% yield) as a clear andcolorless oil (bp 130° C./3 mm Hg (air bath temp)). ¹H NMR (300 MHz,CDCl₃); δ 4.04, J=6.6, 2H), 2.27 (t, J=7.4, 2H), 1.63-1.58 (m, 4H),1.30-1.25 (m, 14H), 0.87-0.80 (m, 6H). ¹³C NMR (75.5 MHz, CDCl₃); δ174.10, 64.47, 34.42, 31.84, 31.39, 29.26, 28.72, 26.00, 24.78, 22.70,22.38, 14.13, 13.96. IR (thin film) 2956, 2929, 2858, 1739, 1466, 1173cm⁻¹. GC ((HP-1 methyl siloxane; f=1.0 mL/min) 100° C. (2 min), 10°C./min, 275° C. (10 min)) 11.05 min.

Example 2 Reuse of a Brønsted Acid Ionic Liquid in the Formation ofEthyl Acetate

The reaction setup used to illustrate the reuse of the IL in synthetictransformations consisted of a 5 mL reaction conical vial equipped witha magnetic spin vane. Attached to the conical vial was a Hinkman-Hinklestill head which itself was equipped with a Claisen adapter and refluxcondenser. Proper alignment of one of the two inlet ports of the Claisenadapter was essential for the addition of reagents via a syringe pump.The setup was equipped with a drying tube packed with CaCl₂ and heatedexternally via a sand bath.

Representative Procedure

To the 5 mL reaction conical vial charged with 2.1 g IL (4.0 mmol) wasadded via syringe acetic acid (1.0 mL, 17.5 mmol) and ethanol (1.0 mL,17.5 mmol). The reaction mixture was allowed to warm to a maximumtemperature of 175° C. (external temperature) over a period of 45 min.Although completion of reaction was observed prior to reaching themaximum temperature, reuse of the reaction setup/IL made it necessary toremove all volatile components via distillation prior to the next cycle.With each cycle, reaction completion was confirmed by GC analysis [GC((HP-1 methyl siloxane; f=1.0 mL/min) 50° C. (2 min), 10° C./min, 275°C. (10 min)) 3.21 min (EtOH), 3.37 min (EtOAc), 3.42 min (AcOH)] anddocumented via the mass of distillate obtained. Each cycle afforded pureethyl acetate without any appreciable amounts of starting material (<7%assuming loss of EtOH due to an EtOH/EtOAc azeotrope (31% by weight andby of 78° C.)). Biphasic mixtures were separated and factored intoproduct formation was maximum water content of 3.3%.

Control Reaction

A 5 mL reaction conical vial was charged with acetic acid (1.0 mL, 17.5mmol) and ethanol (1.0 mL, 17.5 mmol). The reaction mixture was allowedto warm to a maximum temperature of 175° C. (external temperature) overa period of 45 min. Observed were no appreciable amounts of distillateeven after continuous heating 30 min after the 45 min window. Thedistillate that was collected consisted of EtOH (97%) and EtOAc (7%).Remaining in the reaction conical vial was AcOH.

Regeneration and Subsequent Reuse of Ionic Liquid

The system after multiple cycles retained a significant amount of mass,primarily water, which correlated to a rise in mass percentage of over151%. Based upon the mass balance of reaction cycles and product yields,the rise in mass consists of water and acetic acid. Removal of the VOCsusing heat (<175° C.) at atmospheric pressure was unsuccessful. However,when the setup was evacuated (10 Ton) and warmed to 65° C. over a periodof 5 hours, observed was the loss in volume contained in the reactionvial. The resulting ionic liquid still contained AcOH (42%) based upon¹H NMR analysis. Using the results from cycle 2, 0.441 mL of water wasadded prior to the addition of ethanol and acetic acid in an effort tomimic the water:IL ratio. This control experiment afforded 1.3 g ethylacetate (87% isolated yield).

Tabulation of the Results from Recycling the Brønsted Acidic IonicLiquid

cycle ethyl acetate, %^(a) 1 82 2 91 3 96 4 81  5^(b) 87 ^(a)Isolatedyield. ^(b)Isolated yield using regenerated ionic liquid (addition of0.441 mL water prior to run).

Example 3 Synthesis and Characterization of Thioether IL 1 and SulfoxideIL 1

Part 1

A 250 mL round-bottomed flask was charged with a magnetic stirbar, 100mL of toluene and 10.0 g (80.6 mmol) 1-butyl imidazole. To this solutionwas then added 10.4 g (80.6 mmol) of 2-(chloroethyl)ethyl sulfide. Acondenser was fitted, and the solution heated to and maintained atreflux for 12 h. During this time, a dense yellow-brown liquid phaseseparated from the toluene. After cooling, the toluene layer wasseparated and discarded, and the lower, ionic liquid layer washed with2×50 mL of diethyl ether. The viscous liquid was dried overnight invacuo (15.2 g, 76%).

Part 2

The imidazolium chloride product from Part 1 (15.2 g, 61.1 mmol) wasdissolved in 100 mL of acetonitrile and treated with 6.4 g (61.1 mmol ofammonium tetrafluoroborate, the suspension stirred overnight. Thesuspension was filtered and the solvent removed in vacuo to leave thetetrafluoroborate salt of the imidazolium cation (15.6 g, 85%).

Part 3

A 100 ml, flask was charged with a stirbar and 1.52 g (5.3 mmol) of thetetrafluoroborate salt isolated in Part 2. This was then dissolved in 50mL dichloromethane and the solution cooled to 0° C. To the cooled,stirred solution was added dropwise a solution of 1.38 gm-chloroperoxybenzoic acid (66.9% peroxide activity by assay, 3.9 mmolactive peroxide) dissolved in 10 mL dichloromethane. The solution wasallowed to warm to room temperature, during which time a whiteprecipitate formed. The solvent was removed in vacuo, and the whitesolid residue extracted with 5×50 mL portions of ether. The by-productm-chlorobenzoic acid was completely extracted into the ether washings,leaving the pale-yellow liquid product.

Characterization Data for Sulfoxide IL 1

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.93 (t, 3H, CH₃), 1.31 (t, 3H,CH₃), 1.36 (m, 2H, CH₂), 1.84 (m, 2H, CH₂), 2.81 (complex m, 2H, CH₂),3.17 (complex m, 1H, CH₂), 3.41 (complex m, 1H, CH2), 4.17 (t, 2H, CH₂),4.73 (t, 2H, CH₂), 7.32 (m, 1H, ring CH), 7.60 (m, 1H, ring CH), 8.91(s, 1H, ring CH). ¹³C NMR (75.56 MHz, CDCl₃, 25° C., ¹H decoupled) δ6.77, 13.42, 19.47, 31.84, 44.07, 46.05, 49.94, 50.10, 122.22, 123.42,136.59.

Characterization Data for Thioether IL 1 (Product Produced in Part 2Above)

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.88 (t, 3H, CH₃), 1.16 (t, 3H,CH₃), 1.30 (m, 2H, CH₂), 1.81 (m, 2H, CH₂), 2.50 (q, 2H, CH₂), 2.91 (t,2H, CH₂), 4.15 (t, 2H, CH₂), 4.34 (t, 2H, CH₂), 7.36 (m, 1H, ring CH),7.47 (m, 1H, ring CH), 8.77 (s, 1H, ring CH). ¹³C NMR (75.56 MHz, CDCl₃,25° C., ¹H decoupled) δ 13.37, 14.62, 19.35, 25.61, 31.57, 31.94, 49.05,49.86, 122.38, 122.85, 136.00.

Example 4 Synthesis and Characterization of Sulfone IL 1

From Thioether IL 1. See Example 3.

A 100 mL flask was charged with a magnetic stirbar, 1.56 g (5.2 mmol) ofthe specified imidazolium tetrafluoroborate salt and 50 mL ofdichloromethane. The solution was then cooled with an ice-water bath. Tothe cool, stirred solution was then added dropwise a solution of 2.82 gm-chloroperoxybenzoic acid (66.9% peroxide activity by assay, 5.2 mmolactive peroxide) dissolved in 15 mL dichloromethane. The solution wasallowed to warm to room temperature, during which time a whiteprecipitate formed. The solvent was removed in vacuo, and the whitesolid residue extracted with 5×50 mL portions of ether. The by-productm-chlorobenzoic acid was completely extracted into the ether washings,leaving the pale-yellow liquid product that slowly crystallizes into alow-melting solid at room temperature. ¹H NMR (300 MHz, DMSO-d⁶, 25° C.,TMS) δ 0.90 (t, 3H, CH₃), 1.23 (t, 3H, CH₃), 1.25 (m, 2H, CH₂), 1.75 (m,2H, CH₂), 3.18 (q, 2H, CH₂), 3.78 (t, 2H, CH₂), 4.18 (t, 2H, CH₂), 4.64(t, 2H, CH₂), 7.36 (m, 1H, ring CH), 7.47 (m, 1H, ring CH), 8.77 (s, 1H,ring CH). ¹³C NMR (75.56 MHz, DMSO-d⁶, 25° C., 1H decoupled) δ 6.54,13.78, 19.25, 31.82, 42.80, 47.51, 49.20, 50.25, 122.90, 123.22, 137.25.

Example 5 Synthesis and Characterization of Thioether IL 2 and SulfoxideIL 2

Part 1

A 100 mL round-bottomed flask was charged with a magnetic stirbar, 50 mLof toluene and 3.29 g (40 mmol) 1-methyl imidazole. To this solution wasthen added 5.0 g (40 mmol) of 2-(chloroethyl)ethyl sulfide. A condenserwas fitted, and the solution heated to and maintained at reflux for 12h. During this time, a dense yellow-brown liquid phase separated fromthe toluene. After cooling, the toluene layer was separated anddiscarded, and the lower, ionic liquid layer washed with 2×50 mL ofdiethyl ether. The viscous liquid was dried overnight in vacuo (7.41 g,89%).

Part 2

The imidazolium chloride product from Part 1 (7.41 g, 35.8 mmol) wasdissolved in 25 mL of acetonitrile and treated with 8.01 g (35.8 mmol oflithium bis(trifluoromethanesulfonylimide). The dissolution of thelatter was quickly followed by the precipitation of LiCl. After stirringovernight, the suspension was filtered and the solvent removed in vacuoto leave the bis(triflyl)imide salt of the imidazolium cation (12.02 g,86%).

Part 3

A 100 mL flask was charged with a stirbar and 1.51 g (3.9 mmol) of theproduct salt isolated in Part 2. This was then dissolved in 50 mLdichloromethane and the solution cooled to 0° C. To the cooled, stirredsolution was added dropwise a solution of 1.00 g m-chloroperoxybenzoicacid (66.9% peroxide activity by assay, 3.9 mmol active peroxide)dissolved in 10 mL dichloromethane. The solution was allowed to warm toroom temperature, during which time a white precipitate formed. Afterstirring for 12 h, the solvent was removed in vacuo, and the white solidresidue extracted with 5×50 mL portions of ether. The by-productm-chlorobenzoic acid was completely extracted into the ether washings,leaving the pale-yellow liquid product.

Characterization Data for Sulfoxide IL 2

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.25 (t, 3H, CH₃), 2.79 (m, 2H,CH₂), 3.0-3.6 (complex m, 2H, CH₂), 3.86 (s, 3H, CH₃), 4.63 (m, 2H,CH₂), 7.35 (m, 1H, ring CH), 7.52 (m, 1H, ring CH), 8.76 (s, 1H, ringCH).

Characterization Data for Thioether IL 2 (Product of Part 2 Above)

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.21 (t, 3H, CH₃), 2.51 (m, 2H,CH₂), 2.91 (m, 2H, CH₂), 3.90 (s, 3H, CH₃), 4.34 (m, 2H, CH₂), 7.32 (m,1H, ring CH), 7.41 (m, 1H, ring CH), 8.65 (s, 1H, ring CH). ¹³C NMR(75.56 MHz, CDCl₃, 25° C., ¹H decoupled) δ 14.49, 25.80, 31.55, 36.43,49.21, 120.00 (q, CF₃), 122.81, 123.72, 136.23.

Example 6 Synthesis and Characterization of Sulfone IL 2

From Thioether IL 2. See Example 5.

In a 100 mL flask charged with a magnetic stirbar, 1.50 g (3.9 mmol)1-methyl-3-(2-ethylsufido)ethyl imidazolium bif(triflyl)imide [productof Part 2 above] was dissolved in 50 mL dichloromethane and the solutioncooled in an ice bath. To the cooled, stirred solution was addeddropwise a solution of 1.99 g m-chloroperoxybenzoic acid (66.9% peroxideactivity by assay, 7.8 mmol active peroxide) dissolved in 20 mLdichloromethane. The solution was allowed to warm to room temperature,during which time a white precipitate formed. After stirring for 14 h,the solvent was removed in vacuo, and the white solid residue extractedwith 5×50 mL portions of ether. The by-product m-chlorobenzoic acid wascompletely extracted into the ether washings, leaving the pale-yellowliquid product. ¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.26 (t, 3H,CH₃), 3.06 (q, 2H, CH₂), 3.58 (m, 2H, CH₂), 3.82 (s, 3H, CH₃), 4.61 (m,2H, CH₂), 8.58 (br s, 2H, ring CH), 8.98 (s, 1H, ring CH). ¹³C NMR(75.56 MHz, DMSO-d⁶, 25° C., ¹H decoupled) δ 6.54, 36.11, 42.80, 47.00,49.20, 50.05, 120.00 (q, CF₃), 123.18, 124.15, 137.82.

Example 7 Synthesis and Characterization of Thioether IL 3 and SulfoxideIL 3

Part 1

A 250 mL round-bottomed flask was charged with a magnetic stirbar, 75 mLof toluene and 11.55 g (120 mmol) 1,2-dimethyl imidazole. To thissolution was then added 14.97 g (120 mmol) of 2-(chloroethyl)ethylsulfide. A condenser was fitted, and the solution heated to andmaintained at reflux for 12 h. During this time, a dense yellow-brownliquid phase separated from the toluene. After cooling, the toluenelayer was separated and discarded, and the lower, ionic liquid layerwashed with 2×50 mL of diethyl ether. The viscous liquid was driedovernight in vacuo, solidifying during that time into a low-melting, tancrystalline solid. (18.06 g, 68%).

Part 2

The imidazolium chloride product from Part 1 (7.70 g, 35.0 mmol) wasdissolved in 25 mL of acetonitrile and treated with 10.04 g (35.0 mmolof lithium bis(trifluoromethanesulfonylimide). The dissolution of thelatter was quickly followed by the precipitation of LiCl. After stirringovernight, the suspension was filtered and the solvent removed in vacuoto leave the bis(triflyl)imide salt of the imidazolium cation (12.20 g,75%).

Part 3

A 100 mL flask was charged with a stirbar and 4.35 g (19.8 mmol) of thechloride salt isolated in Part 1. This was then dissolved in 50 mLdichloromethane and the solution cooled to 0° C. To the cooled, stirredsolution was added dropwise a solution of 5.10 g m-chloroperoxybenzoicacid (66.9% peroxide activity by assay, 19.8 mmol active peroxide)dissolved in 10 mL dichloromethane. The solution was allowed to warm toroom temperature and stir for 12 h, after which time the solvent wasremoved in vacuo, and the white solid residue extracted with 5×50 mLportions of ether. The by-product m-chlorobenzoic acid was completelyextracted into the ether washings, leaving the pale-yellow glass thatwas shown by NMR to still contain m-chlorobenzoic acid. The glass wasthen dissolved in 50/50 (v/v) acetonitrile/methanol and chromatographedon silica gel. Elution of a pale yellow band gave the product ILsulfoxide chloride salt as a yellow glass that liquefies upon modestheating (2.4 g, 50%).

Characterization Data for Sulfoxide IL 3

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.32 (t, 3H, CH₃), 2.72-3.06(complex m, 2H, CH₂), 2.86 (s, 3H, CH₃), 3.20 (m, 1H, CH), 3.86 (m, 1H,CH); 3.93 (s, 3H, CH₃), 4.68-4.92 (complex m, 2H, CH₂), 7.62 (d, 1H,CH), 8.60 (d, 1H, CH).

Characterization Data for Thioether IL 3 (Product of Part 2 Above)

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.28 (t, 3H, CH₃), 2.54 (m, 2H,CH₂), 2.26 (s, 3H, CH3), 2.90 (m, 2H, CH₂), 3.81 (s, 3H, CH₃), 4.50 (m,2H, CH₂), 7.22 (d, 1H, ring CH), 7.27 (d, 1H, ring CH).

Example 8 Preparation and Characterization of Sulfoxide IL 4

A 50 mL flask was charged with a magnetic stirbar, 1.0 g (4.2 mmol) ofSulfoxide IL 3 (Example 8) and 10 mL of deionized water. In a separateflask shielded from light, 0.40 g (4.5 mmol) sodium dicyanamide wasdissolved in 10 mL of deionized water. To this solution was added 0.77 g(4.5 mmol) silver nitrate, and the solution stirred for four hours. Atthe end of this period, the suspended solid (AgC₂N₃) was quicklyrecovered by filtration, washed with a small portion of water, and addedinto the flask containing Sulfoxide IL 3. This flask was stirred in thedark for two hours, after which time the precipitated silver chloridewas removed by filtration. Removal in vacuo of the water from theyellow-orange solution gave the viscous yellow-brown liquid product(0.95 g, 3.6 mmol, 85%). ¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.30 (t,3H, CH₃), 2.68-3.01 (complex m, 2H, CH₂), 2.86 (s, 3H, CH₃), 3.22 (m,1H, CH), 3.90 (m, 1H, CH); 3.91 (s, 3H, CH₃), 4.61-4.90 (complex m, 2H,CH₂), 7.58 (d, 1H, CH), 8.47 (d, 1H, CH).

Example 9 Preparation and Characterization of Sulfoxide IL 5

Part 1

A 100 mL flask was charged with a magnetic stirbar and 8.0 g (94 mmol)N-methyl pyrrolidine. To the amine was added 40 mL of acetonitrile and14.0 g (96 mmol) 2-chloroethyl ethyl sulfide. The solution was thenheated at reflux for 24 h, after which time the volatiles were removedin vacuo. The sticky tan-brown residue was repeatedly washed with smallportions of toluene and then ether. The impure product was taken up into50/50 v/v acetonitrile/methanol and filtered through a short silicacolumn. The solvent was removed in vacuo leaving a tan solid (5.9 g,27%, unoptimized).

Part 2

A 100 mL flask was charged with a stirbar and 2.0 g (8.6 mmol) of thepyrrolidinium chloride salt isolated from Part 1. To this solid wasadded 25 mL of acetonitrile and 2.5 g (8.6 mmol) lithiumbis(trifluoromethylsulfonyl)imide. The dissolution of the latter wasfollowed by precipitation of lithium chloride, which was removed byfiltration. Evaporation of the acetonitrile gave a viscous, pale yellowliquid (3.3 g, 80%).

Part 3

The product isolated from Part 2 (6.9 mmol) was dissolved in 50 mLdichloromethane in a 100 mL flask that had also been charged with amagnetic stirbar. To this stirred solution was added 1.78 g ofm-chloroperoxybenzoic acid (66.9% peroxide activity by assay, 6.9 mmolactive peroxide) dissolved in 10 mL dichloromethane. The solution wasstirred overnight, during which time a white solid formed. The solventwas removed in vacuo and the white solid residue extracted with 4×50 mLportions of ether. The by-product m-chlorobenzoic acid was extractedinto the ether washings, leaving a viscous, colorless liquid product.

Example 10 Synthesis and Characterization of THF-Appended Ionic Liquid 1

Part 1

Under an atmosphere of argon, a 100 mL flask equipped with a stirbar andfitted with a reflux condenser was charged with 10.0 g of a 50 wt. %solution of tributylphosphine (24.6 mmol phosphine) in toluene. Whilemaintaining the inert atmosphere, 3.0 g (25.0 mmol) tetrahydrofurfurylchloride was added and the solution brought to reflux. After 12 h, awhite solid had precipitated which was isolated by filtration (7.49 g,94%).

Part 2

The solid chloride salt isolated in Part 1 was dissolved in 75 mL ofacetonitrile, giving a colorless solution. To this stirred solution wasadded 6.64 g (23 mmol) of lithium bis(trifluoromethylsulfonyl)imide.Dissolution of the former in the acetonitrile was followed in a shortperiod of time by the precipitation of lithium chloride. After stirringfor two hours, the solid was removed by filtration and the solventstripped in vacuo. The residual colorless oil was washed with 3×20 mL ofether and dried in vacuo, leaving a colorless oil (10.8 g, 82%).

Characterization Data for THF-IL 1

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.95 (t, 9H, CH₃), 1.51 (br,unresolved m, 12H, CH₂), 1.62-2.62 (br, complex overlapping m, 12H,CH₂), 3.4-3.9 (overlapping m, 2H, CH₂), 4.18 (br, 1H).

Example 11 Synthesis and Characterization of THF-Appended IL 2

In a 250 ml, flask equipped with a magnetic stirbar, 10.0 g (99 mmol) offurfuryl amine was dissolved in 100 mL of deionized water. To thestirred solution was added 18.1 g of a 48 wt. % solution oftetrafluoroboric acid in water (99 mmol acid). After stirring for twodays, 1.49 g (49.5 mmol) of powdered formaldehyde was added to theyellow solution, which was then heated to 70° C., at which point themixture became homogeneous. The solution was then cooled to roomtemperature, at which point 7.2 g of 40% aqueous glyoxal (49.5 mmolglyoxal) was added and stirring continued for 3 h during which time thesolution became orange-brown in color. The aqueous solution was thenextracted with three 100 mL portions of dichloromethane, which were thencombined and dried over magnesium sulfate. The solid was then removed byfiltration and the solvent removed in vacuo, leaving a relatively mobilered-brown liquid 11.6 g (38 mmol, 76%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS; mixture of all diastereoisomers;relative integrations) δ 1.56 (m, 2H, CH₂), 1.90 (m, 4H, CH₂), 2.13 (m,2H, CH₂), 3.79 (m, 2H, CH₂), 3.86 (m, 2H, CH₂), 4.06 (m, 2H, CH₂), 4.17(m, 2H, CH2), 4.37 (m, 2H, CH), 7.44 (m, 2H, ring CH), 8.77 and 8.79(singlets, 1H, ring CH).

Example 12 Synthesis and Characterization of Cyclic Amide Appended IL 1

In a 100 mL flask charged with a stirbar and flushed with argon, 5.0 g(23.8 mmol) of 2,4,6-trimethylpyrylium tetrafluoroborate was suspendedin 40 mL of dichloromethane. To the stirred suspension was added 3.4 g(24 mmol) N-(3-aminopropyl)pyrrolidinone. The suspension was stirredovernight at 40° C., during which time the starting tetrafluoroboratesalt dissolved and a red-orange solution was obtained. The solvent wasremoved in vacuo, producing a sticky brown solid. The solid wasdissolved in 30 mL of acetonitrile and flash filtered through a shortplug of silica gel, the silica retaining some degree of color. Thecollected eluant was evaporated, leaving a red-brown oil. ¹H NMR (300MHz, CDCl₃, 25° C., TMS) δ 2.04 (m, 4H, CH₂), 2.33 (m, 2H, CH₂), 2.49(s, 3H, CH₂), 2.79 (s 6H, CH₃), 3.47 (overlapping m, 6H, CH₂), 7.46 (s,2H, CH).

Example 13 Synthesis and Characterization of Cyclic Amide Appended IL 2

Part 1

A 250 mL flask fitted with a reflux condenser is charged with a stirbar,100 mL of acetonitrile, and 5 g (35 mmol)N-(3-aminopropyl)pyrrolidinone. To the stirred solution is added 17 g ofsodium bicarbonate (excess) and 26.6 g (158 mmol) propyl iodide. Thesolution/suspension was heated to reflux for 12 h. After cooling, thesolids were removed by filtration and the solvent removed in vacuo,leaving a tan solid. The solid was spectroscopically determined to beimpure. It was then dissolved in 10 mL of acetonitrile, and loaded ontoa silica column (2 cm×16 cm). The column was eluted with a solventgradient that changed from pure acetonitrile to pure methanol. Theproduct eluted with the methanol rich fraction. The solvent was removedin vacuo, leaving a white solid (6.8 g, 20 mmol, 57%).

Part 2

The product from Part 1 was dissolved in 50 mL of acetonitrile andtreated with 5.7 g (20 mmol) lithium bis(trifluoromethylsulfonyl)imide.Within a short time, the latter had dissolved and this was then followedby the precipitation of lithium chloride. After stirring overnight, thesolid was removed by filtration and the solvent removed in vacuo,leaving a colorless viscous liquid.

Characterization Data

¹³C NMR (75.56 MHz, CDCl₃, 25° C., ¹H decoupled) δ 10.96, 15.99, 18.16,21.36, 31.07, 40.07, 48.30, 57.58, 60.92, 121.02 (q, CF₃), 176.19.

Example 14 Synthesis and Characterization of Acyclic Amide IL 1

Part 1

In a 250 mL flask charged with a stirbar and flushed with argon, 10.0 g(80 mmol) N-(3-aminopropyl) imidazole was dissolved in 100 mL of diethylether. To the stirred solution was added dropwise 6.3 g (80 mmol) acetylchloride. Within seconds the solution became cloudy as the hydrochloridesalt of the acetylamino propyl imidazole salt precipitated. Afterstirring for 1 h, the product was isolated by filtration, washed with2×10 mL of ether and dried in vacuo (16.2 g, 80 mmol, 100%).

Part 2

The hydrochloride salt isolated in Part 1 was dissolved in 25 mL ofwater, and a stoichiometric quantity of solid sodium hydroxide pelletsadded in small portions, taking care that the solution temperature didnot exceed 50° C. Some granular crystalline solid formed as the reactionproceeded. After 3 h, the solution was extracted with 3×100 mL ofdichloromethane. The extracts were combined, dried over anhydrousmagnesium sulfate and the solvent removed in vacuo. The isolated productwas a colorless liquid (11.7 g, 88%).

Part 3

The acetylated imidazole product isolated in Part 2 (70 mmol) wasdissolved in 50 mL of dichloromethane in a flask fitted with a magneticstirbar and reflux condenser. To the stirred solution was added 10.0 g(70.4 mmol) methyl iodide. The solution was heated to 40° C. for 12 h,after which time the solvent and excess methyl iodide were removed invacuo. The residue was washed with 2×25 mL of ether and dried in vacuo,leaving a colorless semi-solid (21 g, 68 mmol).

Part 4

The product of Part 3 (21 g) was dissolved in 100 mL of acetonitrile and7.5 g (72 mmol) ammonium tetrafluoroborate added as a solid. Theresulting suspension was stirred overnight, after which time the solventwas removed in vacuo. The sticky residue was extracted with 4×100 mL ofdichloromethane, and the solids removed by filtration. Removal of thesolvent in vacuo yielded the desired product as a viscous liquid (21.1g, 78%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS; some peaks are doubled due to theobservation of both amide rotomers) δ 2.07 and 2.08 (s, 3H, CH₃),2.19-2.29 (overlapping m, 2H, CH₂), 3.28 (overlapping q, 2H, CH₂), 4.05(s, 3H, CH₃), 4.45 (t, 2H, CH₂), 7.25 (m, 1H, ring CH), 7.58 (m, 1H,ring CH), 7.65 (br s, 1H, N—H), 9.79 (s, 1H, ring CH).

Example 15 Synthesis and Characterization of Acyclic Amide IL 2

In a 250 mL flask charged with a magnetic stirbar, 10.0 g (36 mmol) of1-butyl-3-ethyl imidazolium iodide was dissolved in 50 mL of deionizedwater. To the stirred solution was added 7.0 g (36 mmol) of sodiumN-acetyl taurine. The solution was stirred overnight, and the waterremoved in vacuo. The gummy residue was extracted with 2×100 mLacetonitrile, the solids removed by filtration, and the acetonitrileremoved in vacuo, leaving the product as a stiff glass (9.6 g, 84%).

Characterization Data

¹H NMR (300 MHz, D₂O, 25° C.) δ 0.88 (t, 3H, CH₃), 1.26 (m, 2H, CH₂),1.45 (t, 3H, CH₃), 1.80 (m, 2H, CH₂), 1.95 (s, 3H, CH₃), 3.04 (m, 2H,CH₂), 3.53 (m, 2H, CH₂), 4.15 (complex, overlapping m, 4H, CH₂), 7.44(m, 2H, CH), 8.72 (s, 1H, CH); amide N—H not obsvd (D₂O solvent).

Example 16 Synthesis and Characterization of Acyclic Amide IL 3,Comprising a Urea Functional Group

In a 100 mL flask charged with a magnetic stirbar and maintained underan argon atmosphere, 3.0 g (21 mmol) of 1-(3-aminopropyl)-2-methylimidazole was dissolved in 25 mL of dichloromethane. To the stirredsolution was added 1.8 g (22 mmol) n-propylisocyanate. After stirringfor 3 h, the dichloromethane was removed in vacuo, leaving a thick oil(4.7 g, 99%). The oil was subsequently redissolved in 50 mL ofacetonitrile and 3.0 g (22 mmol) methyl iodide added. The solution waswarmed to 40° C. and stirred at that temperature overnight[caution—overheating can result in the formation of undesiredby-products from O-alkylation]. After cooling, 6.02 g of lithiumbis(trifluoromethylsulfonylimide) was added. Stirring was continued foran additional four hours, and the solvent then removed in vacuo. Thebrown residue was extracted with 4×100 mL of dichloromethane, filteredand the solvent again removed in vacuo, leaving a yellow oil (7.6 g,66%).

Characterization Data

¹H NMR (300 MHz, CD₃CN 25° C., TMS) δ 0.89 (t, 3H, CH₃), 1.24-1.44(complex m, 2H, CH₂), 1.81-1.95 (complex m, 2H, CH2), 2.26 (s, 3H, CH3),3.05 (m, 4H, CH2), 4.10 (m, 2H, CH2), 3.81 (s, 3H, CH₃), 5.15 (br s, 1H,NH), 5.25 (br s, 1H, CH), 7.36 (d, 1H, ring CH), 7.46 (d, 1H, ring CH).

Example 17 Synthesis and Characterization of Amine Appended IL 1

In a 500 mL flask charged with a magnetic stirbar and fitted with areflux condenser, 26.0 g (270 mmol) 1,2-dimethyl imidazole was dissolvedin 200 mL of absolute ethanol. To the stirred solution was added 58.6 g(270 mmol) 3-bromopropyl amine hydrobromide. The solution was stirredunder reflux for 12 h, during which time a copious amount of solidprecipitated. The solvent was then removed in vacuo, leaving a stickywhite mass. This residue was dissolved in 150 mL distilled water, andthen 10.8 g of solid sodium hydroxide added in small portions withstirring. The solution became warm, and slowly precipitated a colorlessgranular solid. After one hour, the water was removed in vacuo, and theresidue extracted into methanol, filtered, and the solvent again removedin vacuo, leaving a stiff yellow glass (59.9 g, 95%). The glass from theprevious step was redissolved in 200 mL of methanol, and 73.5 g (255mmol) lithium bis(trifluoromethylsulfonyl)imide added as a solid. Afterstirring overnight, the solvent was removed in vacuo and the residueextracted with 3×100 mL of 50/50 dichloromethane/ethanol. The solidswere removed by filtration, and the solvent removed in vacuo, leaving ayellow liquid (82.3 g, 190 mmol, 75%).

Characterization Data for Amine IL 1

¹H NMR (300 MHz, CD₃OD, 25° C., TMS) δ 2.01 (m, 2H, CH₂), 2.56 (s, 3H,CH₃), 2.80 (m, 2H, CH₂), 3.72 (s, 2H, CH₂), 4.15 (m, 2H, CH₂), 7.29 (d,1H, CH), 7.30 (d, 1H, CH); NH obsvd as a broad lump in the baselinearound 4 ppm.

Example 18 Synthesis and Characterization of Amine Appended IL 2

In a 100 mL flask fitted with a stirbar and reflux condenser, 5.0 g (36mmol) of 1-butyl-2-methyl imidazole was dissolved in 40 mL of absoluteethanol. To the stirred solution was added in one portion 10.3 g (36mmol) of N-(2-bromoethyl)diisopropyl amine hydrobromide. The resultingsolution was heated under reflux for twelve hours, after which time 1.5g (36 mmol) of sodium hydroxide was added and stirring continued for anadditional four hours. The solution was filtered and the solvent removedin vacuo, leaving a pale yellow mass. The residue was subsequentlydissolved in 100 mL of methanol, and then 2 mL of water and 8.0 g(excess) potassium hexafluorophosphate was added. After stirringovernight, the suspended solids were removed by filtration and thesolvent removed in vacuo. The residue was re-extracted intodichloromethane, the suspended solids removed by filtration and thesolvent removed in vacuo, leaving the product as a yellow oil (9.5 g,64%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.82 (overlapping m, 15H, CH₃),1.37 (m, 2H, CH), 1.79 (m, 2H, CH₂), 2.54 (s, 3H, CH₃), 2.78 (m, 2H,CH₂), 2.94 (m, 2H, CH₂), 4.11 (m, 4H, CH₂), 7.27 (d, 1H, CH), 7.33 (d,1H, CH).

Example 19 Synthesis and Characterization of Amine Appended IL 3

In a 250 mL flask charged with a magnetic stirbar and fitted with areflux condenser, 10.0 g (81 mmol) 1-butyl imidazole was dissolved in100 mL of absolute ethanol. To the stirred solution was added 17.5 g (81mmol) 3-bromopropyl amine hydrobromide. The solution was stirred underreflux for 12 h, during which time a copious amount of solidprecipitated. The solvent was then removed in vacuo, leaving a stickywhite mass. This residue was dissolved/suspended in 100 mL of methanol,and then 3.2 g of solid sodium hydroxide added in small portions withstirring. After four hours, the suspension was filtered and the solventwas removed in vacuo. The residue was extracted into acetonitrile (100mL) and 23.1 g lithium bis(trifluoromethylsulfonyl)imide added as asolid. After stirring overnight, the solvent was removed in vacuo andthe residue extracted with 3×50 mL of 75/25 (v/v)dichloromethane/ethanol. The solids were removed by filtration, and thesolvent removed in vacuo, leaving a yellow liquid (17.3 g, 42%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.88 (t, 3H, CH₃), 1.29 (m, 4H,CH₂), 2.07 (m, 2H, CH₂), 2.70 (m, 2H, CH₂), 4.01 (br s, 2H, NH₂), 4.20(m, 2H, CH₂), 4.43 (m, 2H, CH2), 7.49 (d, 1H, CH), 7.58 (d, 1H, CH),8.98 (s, 1H, CH).

Example 20 Synthesis and Characterization of Amine Appended IL 4

Under an argon atmosphere in a 100 mL flask equipped with a magneticstirbar and reflux condenser, 5.0 g (19 mmol) triphenylphosphine wasdissolved/suspended in 50 mL of absolute ethanol. To the stirredsolution was added 4.7 g (19 mmol) N-(3-bromopropyl)dimethyl aminehydrobromide. The mixture was stirred under reflux for twenty fourhours, after which time the solvent was removed in vacuo. The solid wasdissolved in 50 mL of water, and 1 M aqueous sodium hydroxide addeduntil the solution pH reached 8.5. The aqueous solution was thenextracted with 3×100 mL of dichloromethane. The organic extracts werecombined, dried over anhydrous magnesium sulfate and filtered. Removalof the solvent in vacuo gave a colorless glass (3.3 g). The glass wasdissolved in 60 mL of acetonitrile, and 2.4 g (7.8 mmol) lithiumbis(trifluoromethylsulfonyl)amide added as a solid. The solution wasstirred overnight, after which time the solution was filtered and thesolvent was removed in vacuo, leaving the product as a viscous liquid(4.7 g, 42% overall).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 1.85 (m, 2H, CH₂), 2.23 (s, 6H,CH₃), 2.60 (m, 2H, CH₂), 3.36 (m, 2H, CH₂), 7.64-7.74 (m, 12H, CH),7.77-7.87 (m, 3H, CH).

Example 21 Synthesis and Characterization of Amine Appended IL 5

In a 100 mL flask equipped with a magnetic stirbar, 4.0 g (14 mmol)1-butyl-3-ethyl imidazolium iodide was dissolved in 50 mL of absoluteethanol. To the stirred solution was added 2.10 g (slight excess) ofsolid sodium tauride. The solution/suspension was stirred overnight,after which time the suspended solids were filtered and the solventremoved from the filtrate under vacuum (1.5 g, 38%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 0.97 (overlapping t, 6H, CH₃),1.40 (m, 2H, CH₂), 1.62 (overlapping m, 6H), 1.91 (m, 2H, CH2), 4.35 (m,2H, CH₂), 4.45 (m, 2H, CH₂), 7.34 (m, 1H, ring CH), 7.40 (m, 1H, ringCH), 10.26 (s, 1H, ring CH). ¹³C NMR (75.56 MHz, D₂O, 25° C., ¹Hdecoupled) δ 13.01, 14.83, 19.07, 31.51, 36.74, 45.08, 49.57, 53.37,122.18, 122.52, 136.23.

Example 22 Synthesis and Characterization of Amine Appended IL 6

In a 100 mL flask equipped with a magnetic stirbar, 10.0 g (60 mmol) ofGirard's Reagent T [(carboxymethyl)trimethyl ammonium chloridehydrazide] was dissolved/suspended in 50 ml, of 1:1 (v/v)acetonitrile/methanol. To the stirred solution was added 17.1 g (60mmol) lithium bis(trifluoromethylsulfonyl)imide. After stirringovernight, the solvent was removed in vacuo. The residue was extractedwith 2×50 mL of acetonitrile, filtered and evaporated to leave acolorglass that solidifies on standing into a low-melting solid (22.3 g,90%).

Characterization Data

¹H NMR (all peaks, combined rotomers (300 MHz, D₂O, 25° C.) δ 1.97 (s),2.02 (s), 2.04 (s), 2.18 (s), 3.26 (s), 3.30 (s), 4.05 (s), 4.21 (s).

Example 23 Synthesis and Characterization of Amine Appended IL 7

In a 100 mL flask equipped with a magnetic stirbar, 5.0 g (29 mmol) of(2-aminoethyl)-trimethylammonium chloride hydrochloride wasdissolved/suspended in 50 mL of deionized water. The pH of the aqueousphase was adjusted to pH 8.5 by the addition of 1 M sodium hydroxide. Tothe stirred solution was added 8.6 g (30 mmol) lithiumbis(trifluoromethylsulfonyl)imide, and the solution stirred overnight.The water was removed in vacuo, and the residue extracted with 3×100 mLof 1:1 (v/v) absolute ethanol/acetonitrile. The combined extracts werefiltered through paper, then flash filtered through a short plug ofsilica gel. Evaporation of the eluate gave the product as a glass (7.97g, 66%).

Example 24 Synthesis and Characterization of Fluoro Alcohol IL 1

In a 50 ml, flask equipped with magnetic stirbar and a reflux condenser,1.0 g (5.2 mmol) of 3-bromo-1,1,1-trifluoro-2-propanol was dissolved in15 mL of acetonitrile. To this solution was added 1.5 g (slight excess)of 1,2-dimethyl imidazole. The mixture was stirred under refluxovernight, after which time the volatiles were removed in vacuo. Theresidues were chromatographed on silica gel, beginning with acetonitrileand eluting in a gradient fashion with increasing proportions ofmethanol. The desired bromide salt eluted with the methanol richfractions. Removal of the solvent in vacuo left a yellow glass (0.43 g,17%). The glass was subsequently dissolved in 25 mL of acetone, and 0.20g (0.88 mmol) silver trifluoroacetate added as a solid. The solution wasstirred in the dark for one hour, after which time it was filtered andthe solvent removed in vacuo, leaving the product as a yellow oil (0.51g, 98%).

Characterization Data

¹H NMR (300 MHz, CDCl₃, 25° C., TMS) δ 2.70 (s, 3H, CH₃), 3.80 (s, 3H,CH₃), 4.18 (m, 1H, CH or CH₂), 4.37 (m, 1H, CH or CH₂), 4.63 (m, 1H, CHor CH₂), 7.19 (d, 1H, CH), 7.40 (m, 1H, CH), 7.74 (br, 1H, OH).

Example 25 Synthesis and Characterization of Fluoroketone IL 1

Under a nitrogen atmosphere in a 100 mL flask equipped with a magneticstirbar, 5.0 g (22.8 mmol) was suspended in 50 mL of dichloromethane. Tothe stirred solution was added 3.4 g (22.8 mmol) trimethyl oxoniumtetrafluoroborate, and the solution/suspension stirred overnight.Removal of the volatiles in vacuo left a low-melting solid (5.15 g,96%).

Characterization Data

¹H NMR (300 MHz, DMSO-d⁶, 25° C., TMS) δ 3.67 (s, 9H, CH3), 7.83 (d, 2H,CH), 8.00 (d, 2H, CH). ¹³C NMR (75.56 MHz, DMSO-d⁶, 25° C., ¹Hdecoupled) δ 56.93, 92.66 (q, CF coupled), 120.62, 124.20 (q, CFcoupled), 129.59, 140.99, 148.22.

Example 26 Synthesis and Characterization of Phosphoramide IL 1

In a 250 mL flask charged with a magnetic stirbar and fitted with areflux condenser, 10.0 g (80 mmol) 1-(3-aminopropyl) imidazole wasdissolved in 60 mL dichloromethane. To this was added first 8.1 g (80mmol) triethylamine, followed by 18.9 g of diphenylphosphinic chloride.The solution was heated to reflux overnight, after which time 60 mL ofdiethyl ether was added. The precipitated solids were removed byfiltration, and the solvent evaporated from the filtrate. The residuewas immediately redissolve in 100 mL of acetonitrile, and 12.6 g(excess) iodoethane added. The solution was stirred at 50° C. overnight,after which time the volatiles were removed in vacuo leaving a yellowoil (15.2 g). Characterization data: ¹H NMR (300 MHz, CDCl₃, 25° C.,TMS) δ 1.50 (t, 3H, CH₃), 2.22 (m, 2H, CH₂), 2.80 (br m, 1H), 3.01 (m,2H, CH₂), 4.20 (q, 2H, CH₂), 4.55 (t, 2H, CH₂), 7.18-7.90 (overlappingm, 12H, CH), 10.02 (s, 1H, CH).

Example 27 Synthesis and Use of Task-Specific Ionic Liquids (TSILs) withTethered Acid Groups

General Considerations

The starting materials N-butyl imidazole, triphenylphosphine,1,4-butane-sultone and 1,3-propane-sultone were purchased from Aldrich.The starting material tributylphosphine was purchased from Cytec. Thereagents trifluoromethane sulfonic acid (Aldrich), p-toluenesulfonicacid hydrate (Aldrich) and bis(trifluoromethanesulfonyl)imide (Rhodia)were purchased commercially. The solvents toluene (Fischer),acetonitrile (Fischer), and diethyl ether (Fischer) were used withoutfurther purification. The ¹H NMR (300 MHz) and ¹³C NMR (75 MHz) spectrawere obtained on a JOEL Eclipse 300 NMR spectrometer in D₂O. Chemicalshifts were reported in parts per million (ppm, δ) and referenced to D₂O(δ 4.88).

Synthesis of IL1

To an acetonitrile solution (150 cm³) of 1,4-butane sultone (47.83 g,0.3513 mol), N-butyl imidazole (43.62 g, 0.3513 mol) was added in smallportions. The mixture was heated and stirred at reflux overnight. Thesolution was concentrated in vacuo resulting in a solid zwitterion. Thezwitterion was washed with diethyl ether (50 cm³) and dried in vacuowith a rotary evaporator followed by overnight vacuum using a mechanicalpump. 90.15 g of white solid zwitterion intermediate was obtained (98.6%yield). To a sample of the dried zwitterion (8.85 g, 0.03332 mol) neattrifluoromethane sulfonic acid (5.10 g, 0.03332 mol) was added. Themixture was stirred at room temperature for 12 hours, resulting in theformation of a viscous ionic liquid product (13.95 g, 100%). ¹H NMR (300MHz, D₂O); δ 8.68 (s, 1H), 7.40 (d, J=1.6, 1H), 7.39 (d, J=1.6, 1H),4.13 (t, J=6.9, 2H), 4.08 (t, J=7.1, 2H), 2.82 (t, J=7.4, 2H), 1.91(quint, J=8.0, 2H), 1.73 (q, J=7.7, 2H), 1.68-1.57 (m, 2H), 1.19 (dt,J=7.7, 7.7, 2H), 0.79 (t, J=7.4, 3H). ¹³C NMR (75.5 MHz, D₂O) δ 135.26,122.64, 122.42, 119.80 (q, J_(C-F)=317.0, CF₃), 50.22, 49.49, 49.10,31.31, 28.26, 21.11, 18.88, 12.75.

Synthesis of IL2

In a toluene solution (200 cm³) of 1,3-propane sultone (19.80 g, 0.1621mol) triphenylphosphine (42.52 g, 0.1621 mol) was added in smallportions. The mixture was heated and stirred at reflux overnight. Thesolution was then concentrated in vacuo with a rotary evaporator. Theresulting solid zwitterion was washed with diethyl ether (50 cm³) anddried in vacuo with a rotary evaporator and mechanical pump (61.88 g,99.3%). A portion of the dried zwitterion (3.47 g, 0.009034 mol) wasacidified by the addition of solid p-toluenesulfonic acid hydrate (1.72g, 0.009034 mol). The mixture of solids was warmed and stirred at 45°C.-60° C. overnight, resulting in the liquefaction of the solids; aftercooling of the liquid the a stiff glass was formed that re-liquefiesbelow 85° C. The presence of water (7-10 molecules per mole of salt) inthe initial salt induces a lower melting point. The anhydrous salt meltsat 180° C. ¹H NMR (300 MHz, D₂O); δ 7.66-7.60 (m, 3H), 7.53-7.44 (m,14H), 7.06 (d, J=8.0, 2H), 3.31-3.21 (m, 2H), 2.89 (t, J=6.9, 2H), 2.11(s, 3H), 1.97-1.80 (m, 2H). ¹³C NMR (75.5 MHz, D₂O); δ 142.21, 139.75,135.29, 135.25, 133.47, 133.34, 130.40, 130.23, 129.42, 125.44, 118.13,116.98, 50.55, 50.33, 20.58, 20.04, 17.94.

Synthesis of IL3

In a toluene solution (10.0 cm³) of tributylphosphine (50% by weight intoluene, 0.0222 mol) 1,3-propane sultone (2.72 g, 0.02227 mol) wasadded. The mixture was heated and stirred at reflux overnight under anargon atmosphere, resulting in the formation of a white precipitate. Thesolution was then concentrated in vacuo with a rotary evaporator to halfit's original volume, and the solid product then isolated by filtration.The zwitterion was washed with diethyl ether (50 cm³) and dried in vacuowith a rotary evaporator and mechanical pump (4.77 g, 66%). The driedzwitterion (4.00 g, 0.0123 mol) was acidified by the addition of solidbis(trifluoromethanesulfonyl)imide (3.47 g, 0.0123 mol). The mixture washeated at 50° C. overnight under argon, resulting in the liquefaction ofthe solids and the formation of a somewhat viscous liquid (7.45 g, 99%)that decreases in viscosity even upon mild (45° C.) heating.

Synthesis of Ethyl Acetate Using an IL as Acid Catalyst

To IL2 (2.1 g, 4.0 mmol) was added via syringe acetic acid (1.0 mL, 17.5mmol) and ethanol (1.0 mL, 17.5 mmol). The reaction mixture was allowedto warm to a maximum temperature of 175° C. (external temperature) overa period of 45 min. Although completion of reaction was observed priorto reaching the maximum temperature, reuse of the reaction setup/IL madeit necessary to remove all volatile components via distillation prior tothe next cycle. With each cycle, reaction completion was confirmed by GCanalysis [GC ((HP-1 methyl siloxane; f=1.0 mL/min) 50° C. (2 min), 10°C./min, 275° C. (10 min)) 3.21 min (EtOH), 3.37 min (EtOAc), 3.42 min(AcOH)] and documented via the mass of distillate obtained. Each cycleafforded pure ethyl acetate without any appreciable amounts of startingmaterial (<7% assuming loss of EtOH due to an EtOH/EtOAc azeotrope (31%by weight and by of 78° C.)). Biphasic mixtures were separated andfactored into product formation was maximum water content of 3.3%.

INCORPORATION BY REFERENCE

All of the patents and publications cited herein are hereby incorporatedby reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

I claim:
 1. A salt represented by 2:

wherein ⁺NR₃ taken together represents piperidinium or pyrrolidinium,wherein one instance of R is alkyl; R″ represents independently for eachoccurrence H or alkyl; R³ represents H; L represents (C(R³)₂)_(n); Zrepresents —SO₃H, —S(O)R″, or —S(O)₂R″; X⁻ represents methanesulfonate,trifluoromethanesulfonate, bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide,(trifluoromethanesulfonyl)(trifluoroacetyl)amide orbis(p-toluenesulfonyl)amide; and n represents independently for eachoccurrence an integer in the range 1-10 inclusive.
 2. The salt of claim1, wherein the salt represented by 2 is:


3. The salt of claim 1, wherein Z represents —SO₃H.
 4. The salt of claim2, wherein X⁻ represents bis(methanesulfonyl)amide,bis(trifluoromethanesulfonyl)amide, bis(benzenesulfonyl)amide, orbis(p-toluenesulfonyl)amide.
 5. The salt of claim 2, wherein X⁻represents bis(trifluoromethanesulfonyl)amide or(trifluoromethanesulfonyl)(trifluoroacetyl)amide.